Welcom’s Magna Cart Flatform Truck
I used to haul a bunch of gear around for conferences, hackathons, and such and one piece of equipment I always kept handy was Welcom’s Magna Cart Flatform Truck.
Compact enough to keep in the trunk of my car, light enough to toss around, and strong enough to support 300 lbs. I bought mine at Fry’s Electronics but I haven’t seen them stocked for a while. You can find them on eBay.