We did a split stay for a 4-night trip in April! We're doing a BC/CR split for a 3-night stay this weekend, and a Poly/BWI split for a 7-night stay in January. We even did split stays for 2-night and 3-night trips last year.
We're the same with packing - at WDW, we usually keep everything in our suitcases anyway. So zipping up the suitcases and bringing them down to the lobby is no big deal. We've been taking a cab in the morning of our transfer, but only because that's worked with our park plans so far. (Wanted to start our DHS day from YC, want to start our MK day from CR, for example.) But in January, we're spending the morning in MK and the afternoon in Epcot the day we transfer from Poly to BWI, so we'll just let Bell Services transfer the bags while we're in the parks.
We love split stays - especially the MK/Epcot area split!