A.G. Russel Bird and Trout or Deer Hunter
Fallkniven WM1
any of various pukkos from Ragweed. I have one from Karensuando
Spyderco Vagabond (discontinued, but available with a quick Google search)
Bark River - no specific recommendations, but they have a few models that would probably fit your size criteria
Atwood Knife and Tool - very small fixed blades, though some may go above your price limit
Anza
You might also consider a custom. $100 won't get you a blade from someone famous, but it might get you a good rig from a part-time guy or someone who is starting out. Since fixed blades are easier to crank out than folders, it seems like many people start making small fixed blades via stock removal. I have a very EDC-able blade by Arno Bernard with a 2.5" blade. Tom Krein has some stuff just over $100. Bonus with a custom maker is you'll probably get a custom sheath in leather or kydex that is very serviceable.