>Would such a device be usable on a subway USB interface (with no high speed mode)?
No (due to intensive isochronous mode use at high speed, which is not present in uhc124 chip)
For SVGA, you need at least an amber chip (A3000 or A2000+A2320) or ECS, or AGA. Shortly, you need a thing to plug between denise and the screen, but not a usb one.
+Gilles.
