Well, I didn't notice if tunalegs has given consideration to another camera.
But...I just have to chime in here. I have FSU gear (Zorki 4, Zorki 1, Zorki-C, Zorki-6, Fed-1, Fed 2, Fed 3, Fed-5, Mir, and likely others, along with lenses. J-8, J-3, and J-12 being favorites). I also have Leica LTM (IIIa, IIIf, IIIc, and lenses to go with them). Oh, and I also have Canon LTM (IIf, IVSB, 7, others?, and Canon lenses to go with them). I love them all and enjoy using them. I like being able to interchange all lenses and bodies (except long FSU lenses). However, its like having lots of children, they all deserve your affectations, but so little time.
Now, it doesn't end there; I also have a Bessa-R. That little Bessa has really changed things...
Lens quality, camera reliability, familiarity, and handling make for the complete experience. With that in mind, the Bessa is such a joy to use. It would be the only LTM camera that I would honestly suggest as a genuine improvement to tunalegs current happy kit. And, I would not suggest replacing the Zorki, but giving it a brother/sister. I can also say that I have yet to have a problem using the J-8 on the Bessa. I seem to nail focus with that lens on *any* of my LTM gear, FSU included. Only the longer FSU lenses seem to have any amount of incompatibility leak through...and it's not horrible if you plan for it.
My Bessa-R was $175 a couple years ago. I still see them at the price, occasionally lower. Deal of the decade if you ask me. Yes, it uses a battery (only if you want the meter, but I recommend it). The battery is a widely available, common A76 size. I use silver oxide...everyone should. Oh, and did I mention hotshoe flash? If its of interest...
Now, we will simply not discuss my M Leicas, Rollei, LF, MF folders, Nikon....oh, I have a problem.