So, looks like I was understanding correctly, the only option that's significantly faster than my f/2 Jupiter 8 (which, BTW, gives very similar results to the example listed above for the f/2 Sonnar -- it's the standard against which I'm comparing anything else for this body/mount) and reasonably affordable (vs. the f/1.4 Nikkor, which would also require adjustment to focus correctly on a Kiev or Contax body) is the f/1.5 Sonnar/Jupiter-3. The Helios 103 is only 1/3 stop faster, though it gives a different rendering in OOF areas. These f/1.5 lenses are a bit more than 2/3 stop faster; enough to let me shoot hand held under streetlights or in office lighting with ISO 250 (say, Double-X, or Foma 400 at the speed many others use).
Looks like the medical profession will be snatching all my spare change for the next three months or so ("You have very good insurance," they tell me, while typing up the bill for $200+ after insurance for a routine semi-annual exam), but I hope to grab either a Sonnar or Jupiter-3 later in the fall or winter.