I move between my rooms and home, and do a bit of traveling. And I hate carrying heavy test suitcases, especially if I have to administer the WAIS and the WMS on one day.
My solution was to get one of those roll-on cabin bags that air hostesses and lawyers use. I was not sure if I'd like it, but it turned out to be fantastic. I got a Samsonite with one small compartment and two biger ones. The client file/s go into the small one, WAIS items into the first big one, WMS items into the second. I also managed to find space for the most frequently used bits of ACS, Wisconsin Card Sorting Test and a few bits and pieces. Front pocket fits pens, business cards and sachets of hot chocolate. It opens from the top, so you can put it beside your chair, unzip it half-way and have convenient access to your test materials without taking up desk space. It takes steps quite well, too.
I would definitively recommend it.