OMG they should include a coffee mug with the coffee warmer. Or at least as a 1BTC addon? It's a perfect combo!
Maybe for 1 or 2 orders, but those ordering 8-pack upgrades aren't going to want that many mugs I'll bet.
They could use them if BFL incorporates an interface to dock the mug with the pump of any cooling subsystem, with the coffee being cycled as the coolant. Perhpas, 50% hash rate increases from the caffeine alone. One caveat: users drinking too much of the coffee may see hash rates appearing to slow down.
But seriously, it would just be kinda cool to have one BFL mug.