I am in the market for a 35mm for my M6ttl. I don't have a lot of money to spend on this, I would have to give up something to get a summcron. I have already a CV 21, 90 APO Lanthar, and a Summicron 50mm latest version. My favorite of the trio is a 50mm but sometimes I would like a wider view, but not quite 21mm wide.

These are my choices as far as I know
35mm Summaron (hard to find a good example, but I do like vintage glass)
35mm CV Pancake II F2.5 (almost too small for my liking)
35mm CV Ultron f1.7 (Fast, most expensive)

I know of Canon and Nikon SM lenses but they are hard to find.

Any advice would be appreciated, and if you have or know of one of the above for sale please let me know.