Colorado's supreme court ruled recently that companies could test employees even though it's legal there, weirdly the decision was based on the rationale that even though it's legal in Colorado it's still illegal on the federal level so it's legal to test for weed and fire based on positive tests. This was also a case of medical marijuana, not recreational.
The difference is alcohol leaves your system pretty fast while pot can test positive for a month or possibly longer after you stop I think depending on the test used. So you can get fired for pot even though you aren't under the influence of it. It'd be like drinking on 4th of July when you're at home and then getting fired on July 28 when your boss sees your Facebook pictures of you drinking and puking.
Some candidates off the top of my head. (But 99% probably aren't getting)
Mark Richt (former Miami qb that could use a fresh start?)
Bill O'brien (It doesn't seem like it's working out in the nfl for him)
Jon Gruden (might as well throw his name in there since it's mentioned every time this job is open)
Kirby Smart (his name is always mentioned when there are openings)
Steve Sarkisian (just because he's available lol)