Let's go with the baseball look. Make the coaches wear football pants and uniform jerseys with numbers.
If you think that's absurd, then look at some of those guys wearing baseball uniforms. Horrific! We should be working on phasing those guys out of uniforms and into something more appropriate. Most of the managers don't even bother wearing the uniform shirt anyway--guys like Francona and Piniella would go with the warm up top anyway.
Let the NFL coaches wear what they want. I love Bellichick--he's just making a mockery of the "official" gear rule. ("I gotta wear something out of that catalog? F-U, I'll take a POS sweatshirt and cut off the sleeves. How's that?) The funny thing is, that sweatshirt thing is catching on. Look at Weis and Al Groh and a bunch of these guys. Classic.
Good for Mike Nolan and Jack Del Rio! More guys should wear suits or, heaven forbid, the Hank Stram blazer. ("Sixty five toss power trap. Sixty five toss power trap, boys. Woo hoo...")