Expression pedals compatible with Boss pedals

[D-L-B]

What other options are there out there other than the massive, ugly terminator's c@ck effort of an expression pedal and the rather expensive looking foot switches that Boss have to offer?
Will anything that's labelled an expression pedal going to work? Which ones are the most usable, give the best sound etc?
Small on price and pedal board footprint would be a bonus.

Edited January 14, 2010 by D-L-B

[Mr. Foxen]

Any momentary switch for the switches. Behringer do one that is solid enough.