Also consider looking at picking up an old road double which you should be able to fudge using inside/outside mounting of chainring and/or choice of hub, sprocket and possible use of spacer behind sprocket if req'd.. this will help re BB length and old sq taper doubles http://sheldonbrown.com/bbsize.html
Trawl this http://www.lfgss.com/thread3372-9.html #
Also consider looking at picking up an old road double which you should be able to fudge using inside/outside mounting of chainring and/or choice of hub, sprocket and possible use of spacer behind sprocket if req'd.. this will help re BB length and old sq taper doubles http://sheldonbrown.com/bbsize.html