Here are two examples that some friends and I made. They were originally designed for a 3rd Edition D&D campaign, but they also worked fine in v3.5.



Dwarven Tunnel Miner

Requirements:
Base attack: 5
Race: Dwarf
Skill: At least 5 ranks in Profession Miner (STR as key ability)
Strength: 16 or more
Other requirements: The character must have been working in a mine for at least 10 years (since dwarves live to around 350 years old, that shouldn't be a problem).

Description:
These specialized workers form the elite of miners. Most of them have grown up in a mine along with family members and are therefore skilled at protecting their mine from orcs and other attackers. If the mine is under siege, it is not unusual to see these miners dig their way out of the mine, and behind enemy ranks.

Advancements by Levels:
LEVEL   BASE ATTACK   SAVES (f,r,w)      FEATS (described later)
-----------------------------------------------------------------
  1          1           1,1,0            Tunnel Expert
  2          1           1,1,0            Rapid Digging
  3          2           2,1,1            -
  4          2           2,2,1            Tunnel Fighter 
  5          3           3,2,1            -
  6          3           3,2,2            Strong Breathing
  7          4           4,3,2            Tunnel Defender
  8          4           4,3,3            -
  9          5           5,4,3            Improved Rapid Digging
 10          5           5,4,3            Master of Tunnels
-----------------------------------------------------------------
Tunnel Expert:
You are an expert of digging tunnels, so tunnels you have dug out (in stone, that is) are immune to cave-ins caused by bad constructioning.

Rapid Digging:
You are skilled at digging fast when it is needed. You may toss a d20 and add the skill modifier of your Profession Miner skill to see how many feet you can dig in one hour. Afterwards, make a fortitude save dc 15 to see if you can manage digging that fast. If the fortitude save fails, you dig only half the amount. This feat can only be used once per day.

Tunnel Fighter
You know the tunnels well, and know where to stand to get maximum efficiency when fighting. You gain a +2 circumstance bonus to both attack roll and AC. This feature only applies to tunnels you have dug out, or have been working in.

Strong Breathing
After working so many years in the mines, you are able to breathe while in a cave with no openings at all. This prevents you from running out of oxygen.
Tunnel Defender
No dwarf gives up his work just like that. Dwarves are stubborn so dwarves with this feature gain +4 STR, +4 AC, and 5hp/level temporary hit points. These bonuses last for 4d4 rounds. You or your tunnel must be under an attack to activate this feat. This feature only applies to tunnels you have dug out, or have been working in.

Improved Rapid Digging
As Rapid Digging, but with no fortitude save.

Master of Tunnels
The feat Tunnel Fighter and Tunnel Defender can be used in any mine or cave, as long as it is made out of stone.





Wallclimber

Requirements:
Dexterity: 18 or more
Alignment: Any chaotic
Climb: 8 ranks or more
Jump: 6 ranks or more
Disguise: 6 ranks or more
Feats: Uncanny Dodge, Point Blank Shot


Description:
These shady characters are specialized in stealth more than head-on-combat. Rogues make excellent wallclimbers, since wallclimbers depend on many of the same skills that rogues do. Solitary people who encounter a wallclimber rarely get out of there alive, but groups of people usually never see them at all.

Advancements by Levels:
LEVEL   BASE ATTACK   SAVES (f,r,w)      FEATS (described later)
-----------------------------------------------------------------
  1          1           0,1,0            Spider Climb
  2          1           0,1,0            Drop attack
  3          1           0,2,1            Detect Law at Will
  4          2           1,2,1             
  5          2           1,3,2            Improved Spider Climb
  6          2           1,3,2            -
  7          3           2,4,3            Forge Arrow
  8          3           2,4,3            Abundant Step
  9          3           2,5,4            -
 10          4           3,5,4            Slow Fall (any distance)
-----------------------------------------------------------------
Spider Climb
With this feat, the wallclimber can climb a wall or a roof, without falling, just like a spider can. Toss a d20 and add your climb skill to the result, to see how many rounds you can stay there. If you take damage from an attack, while spider climbing, you must succeed a climb check to stay there, or you will fall down. The DC of this climb check equals the damage you received.

Drop Attack
Useful in combination with Spider Climb. This feat allows the wallclimber to drop down from your hiding-spot, to perform a sneak attack on your foe. The victim must be unaware of your presence, which allows you to add any sneak attack damage you may have. The height of the Drop Attack can not exceed 5 feet/character level.

Detect Law at Will
Just like a Paladin's "Detect Evil".

Improved Spider Climb
As Spider Climb, but with no climb check, if you receive damage, and you can stay there for as long as you wish.

Forge Arrow
This feat lets the Wallclimber make special arrows. Make an intelligence check and add your wallclimber level to the result. If the total equals, or exceeds, the DC, the arrow is successfully forged. It takes one hour to forge each arrow, and you cannot have more than one of each. The arrows last for a week. The arrow always does normal damage, in addition to the spell-like effects. If the victim succeeds the save, the arrow still does normal damage.
DC      Type
--------------
15      Mark
18      Stun
20      Sleep
23      Spy
25      Kill
Mark: If you hit someone with this arrow, and they fail a will save (DC 15), you will know their exact location. The effect lasts for 1 week.
Stun: If the victim fails a will save (DC 18), he/she is stunned for an amount of rounds equal to the damage inflicted by the arrow. The victim can think, see, and feel anything, but is unable to move his body
Sleep: As Stun, but the victim falls asleep instead, and the save DC is 15.
Spy: If the victim fails a will save (DC 18), you are able to see through his/her eyes when you want to. The effect is guaranteed to last for at least one day. Each day after the first, the victim has to succeed the will save again, or the effect continues. The effect can not last for more than 1 week. The victim is unaware of the effect, unless he/she uses 'Detect Scrying' successfully.
Kill: The victim must succeed a fortitude save (DC 15) or die.

NB: The DM may add components needed for these arrows.

Abundant Step:
See player's handbook. This was originally a monk special ability.

Slow Fall (any distance):
See player's handbook. This was also meant for monks.