UPDATE: I updated my ASPI driver, and tried BQFlasher again, and it did run. But it hung on the start of flashing. Thank god the drive was OK after rebooting. So next I tried WinDWFlash, with the same result -- hung on the flash burn step. Again, the drive was OK. So finally, I booted to DOS and tried the Dangerous Brothers CVT flasher (with CVT from their site), and it worked!
I finally have a true "Benq" 1640, and the QSuite tools. I have no idea why it was so hard to get it flashed, but I suspect my system has acquired a few too many bugs over the years. Thanks for all the help zebadee and pinto2!