So far I shoot primarily with my Rolleiflex 2.8E but I want a longer lens for headshots. I've got in close with Rolleinar 1 and 2 and I like the look but it just isn't the look that I want.

I intend on using one lens (150 or 180), one back (but I'd grab another as a spare), and just a WLF.
I reading up on the SL66 from here
http://www.sl66.com/pg/sl66.shtml

but I'm not so familiar with the other Rolleiflex SLR's so if there is one more appropriate then let me know but as I have suggested, i am looking for the simplest camera to do the job.

Hasselblad:
The way I see it, Hasselblad is the benchmark of 120 SLR's, it has the more lenses, accessories, probably cheaper overall, and is more readily available and serviceable. While this is all good...I don't really need the other lenses, accessories, and since I'm looking for a simple settup and sp the overall cost and availability s probably not going to be a deal breaker.

Rolleiflex:
Well the main benefit of the Rolleiflex over the Hasselblad is the tilt feature (not sure if the bellows feature is a deciding factor) which I find to be very cool. Honestly, one big reason why I would want a Rolleiflex over a Hasselblad is my loyalty to the brand. I love my Rolleiflex, a lot. It's a stupid romantic attachment. I thought about a tele-rollei but I think 135mm is too short and the cameras are more for collectors.