Wow! Thank you very much for the photos and the dump!
More info: I've researched a bit about slim TEAC drives and can now suggest which series used the Pioneer hardware:
DV-W28ECxx - DVR-K17
DV-W28SLCxx - DVR-K17 (with slot loader not made by Pioneer)
DV-W28E-Rxx - DVR-KD08
DV-W28S-Rxx - DVR-TD08
DV-W28S-Vxx - DVR-TD09
DV-W28U-Vxx - DVR-TD09 (external drive)
Maybe there are more rebadged Pioneer drives, we have yet to figure it out.
jadburner, have you ever heard of Toshiba Portable SuperMulti Drive PA3834U? It seems that this drive is also a rebadged Pioneer, but I've failed to find any firmware for it to check out.