I did this-- used a shimano deore crankset and just pulled the two smaller chainrings off the thing. (this is on a steamroller/road frame) I used the BMX shorter chainring bolts.

The chainline was all wrong-- and I actually dumped the chain because of it. So I flipped the chainring from the outside of the crank (where it sat lovely in the crank) to the inside. That made the chainline better, but still not perfect. BUT since the ring had nothing to sit on, and bolts aren't really made to deal with a ring just floating on them, the chainring started shifting around while I was riding. Now I just tighten the chainring bolts daily, which is a pain in the ass, but it works.

Long story short-- just buy a damn track crank if you can afford it. Saves headaches.