yer i also wanted to do a higher power DIY. Can you purchase directly from CNI laser?
They have a series that goes up to 800mw. Although its not your normal 12mm,
I dont see why this wouldn't work in a custom host.
If that's the module I think it is, it has no external lenses, and something like 12mRad divergence. You can order direct from CNI, however you'll most likely receive a 'go away' price because they don't like dealing with single orders. And, that being 800mW, you're probably looking at nearly $1000 for the module.