Thunderbolt ports have 10 watts of power available (up from the 8 that Firewire 800 carries). I can't find a spec that shows what voltage it runs at though. Firewire was 12 volt, USB 5v.

As for the VGA and DVI compatibility, that can work two ways. The more widespread method is via a passive adaptor and a dual mode DisplayPort. This requires a TMDS generator to remain on the video card side for the backwards compatibility. Future DisplayPort connectors may be pure DisplayPort without the TMDS, and would require a more expensive active adaptor.

Mini Displayport is part of the DisplayPort 1.2 spec, and that was published in December 2009. AMD already uses it in a few video cards, including their "Eyefinity" 6 display out cards. The board only has enough TMDS and clock chips to support a few ports running DVI, so it requires either a handful of active adaptors, or DisplayPort monitors. We had one of the cards at Vigil, but never did cobble together the setup to run all 6 displays.