Hi John. I have the exact same problem. I noticed that if you hit a point of 'no return' during the Win7 installation/upgrade this past weekend. You can't bail out. There's something REALLY buggy about this installation now.
So one is left to having to boot off a DVD, but they no longer ship with the newer MacBooks. Arrrghhhh!! Just this past hour, I popped into the Emeryville, CA Apple Store, requesting a DVD, but they no longer have them, nor do they have the DVD media in store!! What thaaaaa????!!
Silly me, I forgot to haul my MacBook with me, because I'm not one to use their help. Macs used to be SO EASY to trouble-shoot in the past.
While there, I was handed a thumbdrive/USB stick, called a Recovery Drive, to boot off of. But in no less that FIVE attempts after inserting it into both USB drives, my MacBook Pro can't see it. So I guess I'm packing up my machine and hauling it back to the store. I'll keep you apprised of the next steps.
NB: I informed the Apple sales persons there's a GREAT deal to be desired in the setup after one completes the BootCamp partition process.
Boot Camp Assistant downloads a driver for USB DVD support. That is what you boot Windows 7 installer from.
you put Apple support on USB thumb drive
You can create a ML isntaller 8GB thumb drive if you saved the dcownload and copied it from where it was and before it got deleted after restart during ML install.