White Industries Eno Cranks (square taper only)
Truvative Stylo SS GXP cranks (external bearing design)
The problem with using most mountain cranks designed for SS for fixed riding is that they don't come in 165 or shorter lengths. I prefer short cranks to ride off road fixed for obvious pedal striking concerns.
For that reason I have a pair of Sugino XD's 165's running middle ring on one bike. I really like them so far. In fact, they might be my crank of choice in the future and the price is right!