FWIW, if anyone is looking for a dead simple bonding tool, I'd suggest Connectify Switchboard: http://www.connectify.me/switchboard/

I'm using it to bond two 4G interfaces (Verizon + Clearwire) on the train at this very moment. Need to remember to bring a USB wifi adapter next time so I can add the Amtrak wifi to the mix!

edit: No linux support though. :/