do yourself a favor and just by a generic padded camera bag that will hold the camera and strap and maybe a coupla filters -- I have one designed for a DSLR and lens that works great.
it will be cheaper, the strap will be wider and bite less, it will protect your camera better and it will make the camera quicker to use -- they don't call them "Never-ready cases" for nothing.
Unfortunately for the last few weeks Keh has nothing but a couple of user guides for the rolleiflex cameras. I'd like to get me an original case in very good condition. My T is like new and I'd love to see it in a rolleiflex case. I have thought of buying a padded camera case, but... Perhaps if nothing comes up this is what I will get. But the rolleiflex cases are really nice with the front part unfolding nicely to take that shot.
With patience one will come up either at KEH or eBay or elsewhere. I'd go ahead and email the popular Rolleiflex repair guys and ask, they may have one lying around. And post a WTB here and elsewhere.
The T will not be bigger, I think the sizes of the bodies apart from protrusions are identical: what is different are the knobs and lenses. I do not know where the T knobs go, or whether it takes scissor straps, otherwise it should fit. Good straps are important and will raise the price. Often you will have to have the straps replaced.
I have a case for my 2.8C and use it frequently. I also use the camera in a Retrospective 20. Depends on the situation. Same applies to my Microflex TLR.
As I recall, some of the holes for the knobs, strap, etc., don't line up exactly because the knobs are slightly lower or higher or forward or backward.