It occurred to me that paul@whooppee.com wrote in gmane.os.netbsd.ports.x86-64:
> And what PCI-E 16x video cards are known to be working?
> Especially with X?

I'm running an Ati radeon x300 (Cheapest PCI-e video card I could find at
the time ... ):

vga0 at pci5 dev 0 function 0: ATI Technologies Radeon X300 (RV370) 5B60 (rev. 0x00)
wsdisplay0 at vga0 kbdmux 1: console (80x25, vt100 emulation)

on an Asus A8N-E, using a 3000+ (No X2). Card seems to work OK with xorg, and
can be made to work with XFree86 too - but this involves overriding the chip
ID, making X think it's actually an RV360, aka radeon 9600. For plain jane
2D this seems to be valid.