I would love something like this also. Some of the default effects i would like to see in RR include fadeing and slideing, these two alone would add a whole lot to the experience. I know you can fadeing with VB, slideing should be possible. I have a pic viewer i just found the other day that was written in VB that has really good fadeing.
I would like some kind of pulseing too, instead of blinking it pulses or fades back and forth between the two states, for indicators.
Transitions for switching screens would be cool with options to slide (any direction) fade to, zoom fade. Others can be added for novelty.
I have this really cool app that does transitions on all your icons when you click them, its called UberIcon http://www.punksoftware.com/ (reference)
I think most computers should be able to handle this stuff, heck i can play UT2004 in my carputer with no problem. Any cheap videocard is more than capable of basic stuff. But not everyone has a beefy carputer and a lot have mini itx systems that seem to have a hard time just playing videos sometimes. So there should be an option to turn all that stuff off.
Doing the effects and or even loading everying under DX would also free up the main cpu to do other things.
overall i think it would add a shinny level of pollish to RR and enhance the user experience a lot.