I've seen a few out there, but thought I'd post my own... Pretty simple...
- (4) 30" 2x6
- (2) 18" 2x6
- (2) 4" 2x4
- (2) Furniture Dolly ($20 at Home Depot
- (26) #10 3" Wood screws
- Screw Gun
- Circular Saw
It's pretty straight forward as you can see, so I'll spare the step-by-step process. I thought about putting some L-brackets and/or supports, but its actually pretty solid as is. I'll probably also get some foam padding to put on the contact points, thought the wood is soft enough that its not going to really damage the paint. For the rear doors, you'll notice the blocks that keep the door from sliding.
I got all the supplies from Home Depot for both these and the Hardtop dolly for under $100!