Wow - well, as I said in my OP - Our beta covered a pretty wide range of cards - often R9 290s, but there were _many_ other ATI/AMD cards that were seeing this crash. The overall group found that the only fix for _any_ of them was installing 14.9 WHQL drivers. I'd give you a list, but seriously, it seems like 'every ATI card in the beta' - which is generally pretty self-explanatory, no?
In terms of OS we've got a pretty good mix of Win 7 and Win 8 - both Intel and AMD machines, wide variance of RAM, etc.
This is one of the biggest reasons I want to see if I can get a build proper to ATI - if this ships to a huge audience on the 25th, and nobody with an ATI card with current drivers can play - I imagine everyone (Gearbox, ATI, etc) will have a bad day. And we can't debug this - it just flat out crashes, with no error or condition to catch - in a place that works just fine until it doesn't. Every other vendor is fine - and even ATI cards with somewhat older drivers.
I love that your request for more info labeled this as answered... that's just crazy.