I did this to a mountain bike with vertical drops and to get a tight chain I:
1) had to choose a gear ratio I was not crazy about (42/18=60in & 3 skid patches)
2) file the dropouts about 1/8" (0.125)
3) grind a "flat" in the axle to get some more adjustment room

I saw that sheldon brown was trying using a quick release axle, cut down to fit inside the dropouts, so only the skewer sticks through the dropouts, and you get some more adjustment room: (scroll down)
http://www.sheldonbrown.com/fixed-co....html#vertical

it seems like that wouldn't be strong enough, but since he tried it, I figured I would try it too, and it DOES work suprisingly well and does not slip.

just be sure to lock your rear wheel, or it might not be on the bike when you return. (I hate QR's for that reason)