Mod Bod
Yes, I use the Vista 64 bit drivers. I had to massage them into the O/S somehow (I can't remember what I did). IIRC, it's the installer that doesn't know how to deal with Win 7 64 (through the full install).
I hate to see that they may be deciding to draw the line on support at Vista. Maybe paid support would be a incentive?
Actually, I think it's just that they have tired of the ADAT interface cards. My studio is highly ADAT dependent in that everything (except for most of my synths) are connected via Toslink through the two Apaches. When I found out that they had discontinued the Apache line a couple years ago, I paniced and ended up finding a spare for $650

Anyway, during that panic stricken time, I was on the phone with them a lot and I just got the feeling that digital audio wasn't something they were much interested in (as a hardware developer) any more.
I've had my Dakota/Montana for at least 9 years now and I have always been remarkably impressed by how well Frontier has kept up with the driver situation. Anybody reading this that uses Frontier audio gear may want to send them a note letting them know you are out there and would be very appreciative of them supporting Win 7 for the legacy ADAT stuff.