Bob,
Kudos in getting your Fed 3b! I had one before and before it made way for a Kiev 4a, it worked very well indeed and came with an excellent I-61 L/D. I miss that camera, but I know it is in good hands and my Kiev is doing nicely, other then the occasional little quirk here and there.
I've short listed three cameras that I would like to get, the Minolta 7sII, the olympus 35RD and the Canon Canonet QL17. All have fast lenses (1.7+) slow shutter speeds plus B, great optics and good finders. I'll recommend them to you to find, though take my advise with a pinch of salt as I do not yet own any of these cameras. Any other camera to me is either has too slow a lens, no slow speeds, no manual operation or is just too big. Also, if you can take Russian Rangefinders, I'm sure you can take Japanese Quality engineering. Get a good model and give it a CLA if needed. It'll work like a charm after. I hope this helps. All the best.
Regards,
Samuel