Duane,
Maybe a little off-topic but please take a look at this post:
http://roland-arranger.com/index.php?option=com_smf&Itemid=38&topic=1798.0

Could you build something like what I'm looking for? Do you know whether one of these vendors sells a footswitch which has a mode for "double pump" (which would accomplish what I'm seeking)? Thanks!