Hi 1skydive,
Your observation is correct - most schools are using R.22s, and most of them are using insurance which requires 200 hours in the R.22.
There are a few more 300CBi's popping up as people figure out that the CBi is as cheap to run as the R.22 over the long haul, but currently the R.22 still dominates the training landscape.
If you go through from beginning to CFII at HAI, you can do your instrument, commercial, and CFII training in either the 300 or the R22 - depending on your choice (and how much you fly in your IFR and Com), you can have anywhere from 50 to 100 hours in the R.22 (I did the IFR and will do the CFII and will probably have about 75 R.22 hours, vs about 130 300CB hours).
There are R.22 schools who will hire you with less than 200 hours, and there are schools with the 200-hour requirement who will make some effort to get you some flying time in other ways (photo flights, etc). There are also Schweizer schools contacting HAI fairly regularly, looking for CFIs.
But the bottom line is, you may indeed have a tougher time finding that first job if you do all your training in the 300CB - that's the choice you have to make, for the time being.