Hi Patrick
In the UK, the exclusive dealers for CA are, as far as I know, Richer Sounds. They are still offering the 650BD, but you're right, the 650R seems to have dissapeared (although RS are showing them as available in some stores)very quickly after release. Perhaps because it's not got very good reviews? And the new CA 3D Blu-ray player's out now, so I guess they'll be pushing that rather than the 650.
I'm in a similar situation, I have a 650BD and have been looking for a 'matching' receiver. After much consideration, I decided to go for a Yamaha RX-V667, but I haven't yet had a chance to try it out.
Of course, if you especially want an all Cambridge setup, you could consider buying used; there seem to be a number of ads for 650R's (and the older units) on the usual websites.
Anyone on the forum from Cambridge Audio who'd like to comment on the situation?