You stated that you are looking for an RT, and this thread has morphed into a discussion on the versions of R1200 RT.
You should seriously consider an R1150 RT, which would fit your budget.
I mistakenly sold an immaculate 2004 R1150 RT a few years ago, and still regret it.
Simpler to own, adequate mpg and performance, and you can whip out the Servo ABS in an afternoon if needed.
Go back to a pre-2001 bike and you have the ABS-2 system, which is very robust.
Be aware that post 2007 bikes have a major issue with the iABS 2 pump, which causes the ABS to deactivate.
The bike is rideable, but you lose the linked brake and ABS functions.
This is becoming more common across all R and K bikes which use the same cheapo €30 motor unit on the ABS pump, and BMW Europe are resisting calls to issue a recall on 2007-2009 bikes.