I want to run 41 x 15, and it's for road use. 36 x 13 is about the same, but cogs so small feel horrid, accentuate any out-of-roundness and aren't as efficient.
It fits OK on my Cannondale M1000 frame, but that has vertical dropouts and the ENO hub never worked properly for me - it kept creeping every time I rode up a steep hill. Hence the frame swap.
Track frames with huge chainrings look cool.
MTN frames with uber small chainrings look cool.
Track frames with huge chainrings look cool.
MTN frames with uber small chainrings look cool.
This is the way of things.
Hope that helps ;)