the one advantage you have with the cmbi is that it is self powered. That is a good thing because you wont need a preamp, but, it can also be a bad thing.
At very high SPL's, although they are self powered, the mics (or the recorder rather) might not be able to handle the high SPL's that the mics are feeding it.
In the case of a preamp, you don't need to worry about it - but when you are relying on the r-09's internal electronics to do that work, you may have some overloads on levels since you have no way of controlling the gain level from the signal right out the back of the microphone.
I hope this makes sense.
I would (if i were you) definitely reconsider. You can sell the cmbi bodies and keep the mk4's/ r-9. For probably the same cost (or maybe less?) than you spent on the cmbi's, you could get a stealthy "NBOX'.
The Nbox is made from high quality electronics which mimic the sound of the cmc6 bodies, yet combine it in a small, portable preamp which would not only power the mk4 capsules but also apply the correct amount of gain. you can get these boxes with either fixed gain or adjustable gain...
the boxes cost around $1150>1250 or so, and include not only the box w/ electronics, but also cables and colletes that the mk4 capsules will screw into. Then you will take the signal out of the nbox via RCA cables, and use an RCA>Mini cord to go into the r-09.
another, yet more expensive option would be the sonosax sx-m2/LS2 (modified sonosax preamp with lemo connectors, and electronics which replace the need for cmc6 bodies). These go for around $1150 or so, but then you'll need to purchase a KCY adapter cable which could run you around $5-600 US.
(i'm in the us so all figures i'm using are USD$)
anyway i hope some of this helps, let us know if you have any other questions or need advice.