Ah, I see. Well the main reason why the Shadow 07/09 will never get an official 6.5 from T-Mobile of course is because development for them from HTC stopped some time ago. The Shadow was never really a big time seller, and HTC is notorious for not supporting devices that don't sell well.
The other reason that an official-ish ROM is unlikely is because of hardware compatability between models. While it's true that the Snap/Dash 3G is technically just an upgraded Shadow, the hardware is COMPLETELY different.
So like I say, the unofficial AllShadow WM 6.5 is probably your best bet for 6.5 on the Shadow. While I can understand your want for an official ROM, custom ROMs are most of the time VASTLY superior to stock or official ROMs. Much less overhead, better preinstalled programs, no crapware etc. I would at least give it a try!
Verizon Motorola RAZR LTE
Acer Iconia A500
Custom Stock 4.0
Acer STOCK 3.0->Custom Stock 4.0
HTC S620 Excailbur->HTC Wizard->HTC Juno->HTC Herald->HTC Tytn II->HTC HD2/HTC Shift 9500->HTC G2/SGT ATT->LG G2X/SGT ATT->HTC Sensation/SGT ATT->Motorola RAZR LTE/Acer Iconia A500
PARADIGM SHIFT!! Now on Verizon USA.