I like Andrew's approach. I gather you have trued wheels but have you built one from scratch? A rear?

I have zero issues with different front and rear rims. Outside of vanity, peer pressure and that wheels often come as sets, there is no good reason to keep them the same. If I were you, I'd ride the 28 spoke rim I liked the looks of up front and a good reliable 36 spoker in back. (You never see that rear rim riding.)

With several wheels under your belt, you may well want to lighten things up on the rear wheel. 1) you'll be building better wheels. 2) you'll be enjoying building wheels so if that sexier rear doesn't last quite as long. you get to build another. Fun!

Keep riding! Keep building wheels! It's a good life.

Edit: A +1 for the last poster, especially for emphasizing build quality. Factory built 36 spoke wheels are quite likely to be mediocre builds and not serve someone of your weight well. (Often they can if the spokes are loosened then re-tightened as a proper build. Factory builds are often the cheapest way to get all the parts. I've purchased quality Shimano hubs laced to Open Pro rims at Performance for $100.) If you build you own, the first (one, two or three) may well be no better but soon your wheels will be a large step up in quality and durability. (And as you build and after, hang out here and at bikeshops to ask and learn more re: wheelbuilding. It's an art, but don't be intimidated, anyone can learn it and there is no one unique approach you have to take. You will talk to engineer/scientists with one approach and measure nothing artists with radically different approaches who all build super wheels that are a joy to ride and own. You can too.

Ben