Geeze thats gonna be sweet :-o :-D
power shouldn't be a problem.
but heat will be in a desktop case. organise some fans to keep the PPC card cool, and to exhaust the hot air out of the case.
maybe replace the PPC heatsink and fan (known to break) with something a little more meaty.
The Cyb64/3D GFX card, (i had one) will be fine. no need for heat sinks or the like. i stuck a heatsink on mine, but more for asthetics than anything.
- note
if you are going to try to use 3D apps, then the Cyb64/3D doesn't really cut it. get either a mediator4000Di with a voodoo3 card, or a CybervisionPPC. (both of those cards NEED heatsinks.)
the video card will be able to output to what ever flatpanel of your choice with that scandoubler. - just you might want to run workbench at its native resolution. 1280x1024 or what ever... its more than capable. :-)
non-native resolution is where the video processor of the monitor has to adjust something like a 320x256 into a 1024x768 - or some such numnber, which is the number of pixels the flatpanel physically has. as a result, it can be fuzzy at best, or at worst. hard on the eyes to the point of migrain inducing.
however modern flat screens are much much better at figuring out how to display non-native resolutions these-days...
flat panels have a physcial limitation with one colour element representing one pixel. hence unless using them at native (one pixel = one element) resolution...
CRTS don't 'really' have that problem. so are much better at multiple resolutions...