Check out this website:
http://www.birthinbinsi.com/index.htm
I quickly tried on one of their skirts at my last midwife appt. It has Velcro down the side so it can be removed easily even with monitors or lines. My midwives have these skirts in their office that they use for some exams, etc and they said I can borrow it for the birth and return it. I'm pretty excited - not a hospital gown, and I save a buck or several! Now, for the top....
I like the idea of the tank top. Again, it comes apart from the side so it won't interfere with IV lines, BP cuffs, etc if you want to remove it NOW. I dont' want to spend $45 though. Maybe a totally cheap tank top that I won't mind cutting off?
I'm going for a VBAC as well. I know I might end up totally naked, but I'm usually fairly conservative and expect to start off pretty modest. However, I totally resent the psychological impact of being a "patient" in a hospital gown - not just me, but everyone who sees me. And, a hospital gown isn't even that user-friendly - you have a totally bare backside, but your front is completely covered. When they have to listen to the baby or adjust a monitor, you will have to have the gown pulled up past your waist. That's where the skirt is so nice.
HTH!