After testing CM7 on the Optimus V the following stuff will need to be changed to get a fully working version on the V:
1) Carrier Text (eri.xml)
2) In voicemail settings put in your phone number (this allows you to dial 1 to check voicemail
3) USB drivers built-in to the OS will likely have to be changed to get ADB and USB Mass Storge to work. USB charging works fine.
4) MMS, this will be tougher to get working. Virgin Mobile uses a heavily modded Mms.apk, it doesn't use system wide APNs so backup and restore of APNs will do nothing. The APNs are hardcoded into the MMS.apk along with alot of other changes to make it work on Virgin. Our options are either make the 2.2 Mms.apk work on CM7 or possibly port those changes to the CM7 Mms.apk, but that would be much harder. Incoming MMS on CM7 shows up garbled and from 9999999999 just like the Intercept when we updated to the Sprint 2.2. This was never able to be fixed, but I believe thats because no one ever tried to port the Mms.apk from 2.1 to 2.2. Virgin Mobile uses some special authentication that is non-standard for their MMS system, so using their modded apk is really the only choice. Porting over all of the kernel changes that zefie has made to the Sprint kernel to our kernel since the source code was released would probably be a good idea as well.
Obviously this is all pretty easy, and it would be wise for someone to port the ClockworkMod recovery to the V as well, as CyanogenMod is made to run with this recovery for certain features to work. The MMS will be the biggest problem, I haven't tried to get the MMS.apk from 2.2 working on 2.3, it may be a matter of just copying it over, but likely it will require some mods to get it working.