Interestingly enough, I'd been interested in them forever floating around on ebay. I bought one some time back and actuallly used it in my G3-upgraded PCC Powerbase.
It was... interesting. This was the "faster" ThunderPower one meant for higher end 604s (no DSP board connections; still there but the pins aren't). It had some interesting (standard on 2D cards at the time) features: pan-n-zoom and setting a virtual resolution higher than the resolution on the display. Performance against my Radeon wasn't impressive for a multi-grand card (I thought it would compete 2D-wise). I honestly think they just plunked their nubus architecture on a pci card. It did have 30-bit DACs, for what's it worth.
Being as Radius always gave the card a name (1600 etc) based on the highest resolution offered in 24-bit, I don't know why they called it the Thunderpower 30/1920 since it only had 6MB VRAM and simply couldn't pull it off.
