One of the big reasons I am using Reaper is for the nicely done plugins - it would be great if with the registration, the plugins could be used with other DAW's. A "Reaper wrapper" to dx(i)'s or vst(i)'s.
The main issues are that in general the REAPER ones depend on a lot of functionality from REAPER (everything from basic UI to being able to read media files etc).. so porting all of them isn't really practical for us..