I found a couple of places online that offer complete conversion kits for the 2002 Durango. Looks like the cost is about $1100 for the kit. It doesn't look too difficult to install either. If you're a half way capable wrench monkey.
yes,'03 was the only gen1 year to have rear discs.i forget the company,but someone also made a viper rear disc conversion kit for the gen 1's since vipers also run 6 lug wheels.several years of '97-04 dakotas also had rear discs as well;this might work as well if you had a different proportioning valve from the dakota meant to work with 4 wheel discs.