As to your tire question: On my 2500, I run Goodyear Wrangler ATS tires (285's). These are Goodyear's premier all-season/all-terrain tires, and I love them. They are already siped to beat the band (have something like 7800 biting edges to them), have a very aggressive tread for snow, mud & sand, 2 wide channels to let water flow & prevent hydroplaning. They handle terrificly and ride smooth and suprisingly quiet on dry pavement. I think they're the best tires I've ever owned (my 3rd set, on 3 trucks).
On my wife's Suburban, I run Michelin LTX M/S tires. These actually have even MORE sipes than the Goodyears, but since she never takes the "burb" off-road, these were recommended for the snow & ice conditions she encounters (we live in Idaho) and it was a very good recommendation.
Michelin makes another tire specifically for snow & ice, with even MORE sipes (there's that word again) than the LTX's, but I'm not certain if they're built for trucks, or only for passenger cars, & I don't know the model name/designation.
I recommend Discount Tire Company if there's one near you. They had the Goodyear & Michelin stores beat on prices (everywhere else too, for that matter, including Wal-mart), and gave a better treadwear warranty (60K) and tire replacement package.
As to removing either set of rear tires, I can just see the $$ lighting up in some bottom-feeding lawyer's eyes if you happen to get into an accident. Sure, the folks here on the TDR may understand the traction/tracking reason you did it, but the idiots who sit on juries and award $3M to some broad who spills her own coffee in her crotch will easily believe that you wrecklessly endangered someone's life. After all, if the manufacturer had meant for your truck to only have two rear wheels, that's how they would have built it, wouldn't they? Who are you to say you know more than Daimler/Chrysler, hmm? Make him PAY, ladies & gentlemen of the jury!!
Yes, I know this is a long post, but honestly, it's the first long post I've had all year.
Regards,
Sam