The issue is that the fork he wants does not support a front brake.

Maybe a foolish question, but I don't suppose a rear brake is possible (since apparently your fork is all that's preventing you from having a front brake)?

A rear brake is, after all, exactly as effective as (or more effective than) your feet for stopping you on a fixed gear. Obviously neither is as effective as a front brake, but if all you are worried about is unclipping (and not the increased stopping distance), than a rear brake may help quell your fears.

This must be weighed against the reality of rear brakes looking way uncool.