I don't know if this was common knowledge, or if anyone even cares, but I thought I'd share. My original AstroTrac TT320 arrived yesterday (Thanks Tom) and I got straight to assembling a tripod setup for it. I took the fairly rigid wedge/top component of a NexStar 5 tripod and bolted it to my Davis & Sanford ST600. It's solid as a rock, so now I'm just waiting on my ball head to arrive.
In the meantime, I wondered if the CG5 Polar Scope could be modified to fit. It does fit, and I mean perfectly. If you take off the rear ring and the retaining ring for the setting circles, the collar of the rear ring fits in the AstroTrac Polar Scope arm. Reassembly is easy, and it's snug and flush with the mount.
It may not be nearly as accurate a polar scope as the genuine AstroTrac one, but it's worth a shot if you have one not in use. I'll try to use it a few times and report back, and the worst that can happen is that I'll just have to purchase the real deal.