I'm looking for a waist-level finder for my new-to-me M645, as well as two lens bottom caps and hopefully a body cap. Those last I can probably find on fleabay, but if someone here has some, or other bits 'n' bobs...
Check KEH for the caps - they always seem to have some of those in stock.
Waist level finder is going to be tougher...but worth the search. I pretty much use mine exclusively on my M645.