JHawk,
I really like the center channel below. My screen is 33" off the floor and with the speaker directly below, I don't have to angle it up. In fact, it is just about in line with the KLF-20's mid-range horn. As far as getting a transparent screen, I never tried it or looked at one. I heard the the sound was OK, but, keep in mind you may have to remove the grill to make up the acoustical difference. There was also a comment about how light leaked through the back and washed out the picture a bit. That might be cured by putting velvet or velour behind the screen.
Scalers: I don't know too much about them.
DVDO has 480P Output only. The FSR MAS-4100 or the TVOne #CSC-1600HP, has selectable outputs to 1080i and are both price competitive with the DVDO. I heard this my from my projector dealer. Check around the net for prices.
JBR