The 645D IR is released today:-
http://www.ricoh.co.jp/release/2012/1212_1.html
(in Japanese, Excite English Translation Here.)
After all, it is essentially a 645D with the IR-cut filter removed. The production volume is targeted to be in 100 units per year, btw. It is further stated that when an IR-cut filter is added back by mounting onto the front thread of the lens, the 645D can be used
