At the very least, I *do* know that the original Studio Display (the midnight blue ones) had a VGA plug. They also used ADB to connect to the Mac for colour correction and other things.
The second generation of this screen was made to match the new Blue and White G3's colour scheme. I think by then it had a USB port to connect to your computer. I also think that it was still a VGA. But I'm pretty sure that the last incarnation, the Graphite model was the first to use the DVI.
Don't know of any vid-card makers that have a DVI-equipped Mac card.
KCUBYE!