David,
Sorry for the late addition to the thread; I hope this opinion still is of any use to you...
About six weeks ago I returned from a trip to Italy with 2 M bodies and five lenses: 15, 21, 35, 50 and 75. One of the cameras was always loaded with color film and the other with B&W, your case will be different. When processed the 30-odd rolls, I observed that 90% of the pictures and almost 99% of the keepers were shot with the 35 and 50. Ditto my last three trips abroad. The ultra-wides and the 75 end up being security blankets.
I would go with just two lenses, 28 and 50 or 35 and 75, leaning heavily towards the first pair.
My own affordable favorites are:
Ultra-wide: Voigtländer Color-Skopar 21/4. Sharp, well corrected, super compact, excellent finder, price roughly equal to the Leica 21 finder alone.
28mm: There's only one option at less than one grand: Voigtländer Ultron Aspherical 28/1.9.
35mm: 4th version Summicron 35/2 (last pre-ASPH). Small, sharp, great bokeh, not too expensive (about $400 used). In case it's too dear, the Color-Skopar 35/2.5 classic is an almost as good substitute with fairly lower build and a stop less of aperture (it matters a lot for interiors).
50mm: No contest, the Summicron 50 in any version, preferably the newer ones. Second place, the Voigtländer Nokton 50/1.5 --heavier than the 'cron and with somewhat harsher bokeh but just as sharp and with one more stop. It also has a nice build with brass barrel that matches the black paint of the MP perfectly. Lettering scheme too.
75/90mm: Voigtländer Color-Heliar 75/2.5. Very sharp from f/4 down and with extraordinary bokeh. Very good build too. 2nd place, Canadian Elmarit 75/2.8. Generally go for around $600.
Good luck with your quest,
--Jorge.