Bobcat Trail 3 as a commuter.

I have a Marin Bobcat Trail 3 as my daily commuter. I want to convert to a 1x8 setup but would like suggestions for a 1x crankset. Also I am a Clydesdale (5'10" - 320 lbs.) and have had to replace quite a few spokes on my rear wheel (Bontrager AT 550 36 spoke) and would like suggestions for a beefier rim to support my size.