i've fixed every version of them, hundreds of times, and years ago did lots of serious body repairs like complete front and rear 'cuts'. its hard to find one that has not been crashed, many of them seriously. they were so expensive in their day, insurers fixed some pretty badly damaged cars and we got a lot of them to do locally.
I reckon you will be looking for a while. I'll bet almost every import has an altererd speedo, some dramtically. There are give-aways.
Even a "good" SW20 is not worth professionally painting, but if you plan on keeping it, then its a "project" and $ dont really matter. I still agree with you, find the straightest, cleanest one you can and worry about paint last. Dont forget, mechaincs are always cheaper to fix than body