There are, but because they apply to ALL WP7 devices, you won't find much in this forum. All of those tweaks and such can be found in the main WP7 General and Dev & Hacking forum.
Also, because DZs (roms for the C900) are hard to come by, crack and build, and the fact that we can't crack our bootloader, there will be no custom roms.
Cingular 8125 → Cingular 8525 → HTC Tilt → HTC Fuze → HTC Tilt 2 → LG Panther → LG Quantum (sigh) → HTC Titan II
HTC Titan II Rom: 7.10.8860
LG Quantum Rom: 7.10.8860
Asus Transformer Rom: Android Revolution HD 3.6
StarTrek Rom: WM6.5 Standard 23017
StarTrek Radio: 126.96.36.199_02.45.30