Sorry for the delay in reply, my mind's been elsewhere now that the project is finished.
I lost about 3 or so arrays of ShiftBrites. No biggie, since we also burned out one Arduino. I still had plenty to make my lights.
The current control register was set lower because I found that with 15 SB's per Arduino, I got all sorts of glitches when at full brightness. Thus, the lowered value. I also scaled my RGB color arrays to 256 rather than 1024 to combat this problem (thankfully I used a Processing sketch to extract and convert these values, otherwise I'd have gotten carpal tunnel w/ all the data entry). Possibly overkill, nonetheless I was crunched for time and the lights work, so problem solved!
There are some photos of the completed installation here:
http://www.spurse.org/spurse/intro.html
http://www.spurse.org/spurse/walkthrough.html
Thanks again for all your help. It was down to the wire, but altogether a very successful project!
~Kyle