Isn't the amount of _free_ vram what wine really is interested in? The information how much RAM the card has is pretty much useless.
And the sysfs approach won't work when using X over ssh or similiar.
That's too bad anyway, since there's no shared memory etc. I would imagine it would be painfully slow to run 3D applications with any nontrivial texture or sizes or geometry complexities over a remote X connection. Especially if textures are dynamic like they became in some games (say an in-game "TV" etc.).
I haven't checked, so maybe I'm well off base here ;)
Cheers, Kuba