Interesting trivia: Zume owns the patent for "cooking on the way". These days you can really patent everything (in USA only, I hope)... What about mobile hot dog stand? Isn't that prior art?
Pizza Hut had a 1984 patent for a mobile delivery/kitchen truck that would cook the pizza en route to the customer.[1] Zume's patent even cites it[1]. Just skimming over both filings, I'm kind of surprised it was issued in the first place.
I'm sure there's enough desperate money like Son's in the VC/PE world that a patent for anything and a decent story can get you a meeting and a term sheet.