Are you after a programmable effects unit?
ie you upload a distortion to pedal one, flanger to number two etc....
not sure they exist where you can use indemendant of the computer (with out spending lots on a programmable dsp chipset)
Native instruments do a nice bit of kit for this 'Guitar rig', but you need the computer connected at all times
http://www.native-instruments.com/index.php?id=guitarrig3
failing that, look at the muse research's receptor
http://www.museresearch.com/receptor.php
this is basically a rack ounted pc that you can run vst plugin's on
one of those and a midi footpedal?
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Monkeyboy ... a.k.a Steve
Shamooli Dawn
Epiphone SG 'Les Paul' Custom > Korg AX1500G > Marshall G30RCD