hmmm I thought those pedals were a little expensive. for a few £ more, I could get a Boss loop station (just the one that's stomp box sized) but it's still a lot... so I've got a usb keyboard, and a couple of spare foot switches, and I'm going to make a USB dual pedal unit

all you need is the ability to solder, and an hour of time.
get a cheap USB kayboard:
http://www.ebuyer.com/product/105529open it up (do not plug it into your PC) and in side will be 2 sheets of transparent plastic. like the stuff used on overhead projectors (before they had projectors that worked with PCs). you'll be able to see that when you press a key, it pushes the sheets togethar and makes 2 contacts join. follow those contacts back to the little circuit board, and use a permanent marker to mark which terminals are used. I found that there's a common pin for the space and return, and there's 2 other connections, one for space, one for return.
now you need 2 pedals:
http://www.stagebeat.co.uk/P/5089/G028Byou then wire up 2 push to make switches for those contacts, and that's it! you'd either need a small box for the circuit board, or it may fit in the pesal enclosure if you get a pedal like this:
http://www.dolphinmusic.co.uk/page/shop/flypage/product_id/6385 although that pedal will need a little rewiring, I think it should do the trick.
as it happens, I have an old USB keyboard and 2 non latching foot switches, so for me, it'll be an hour of time, and no cash... BARGAIN!
Perhaps Sonoma should come our with their own optional USB footswitch, then add a few extra looping features, and it's an extra feature

Regards
Rowbi