The biggest problem with all of these commercially available cargo slides is their otherworldly cost. If someone was able to make one that was even halfway reasonably priced, they'd sell as many as they could produce!
Price and weight. Don't forget that a JK has a GVWR that's Prius sized.
I like Front Runner's cargo slide, especially when used in conjunction with their interior rack. I find them elegantly simple and, thus, functional and flexible. Pretty close to ultimate, in my view. My only complaint is that the cargo slide is sized to accommodate the sub-woofer. So, for those JKs without the sub-woofer or the 2015s with the sub-woofer recessed in the floor, the cargo slide does not span the entire width of the cargo area. Front Runner should make two sizes.
I mentioned in the first post of this thread that I have friends at a company that manufactures slides for RVs, here are some photos of their products. They make a range of slide products, ranging from a the smaller slides at the bottom right that retail starting less than $150, up to larger 800-lb capacity slides (bottom left) that retail starting around $300.
They make a wide range of sizes, so when we come to some conclusions here in this thread about a good size for the Jeep application, I'll see if they have one that size already, if not they'd probably be willing to make up one to a custom size for me.
I'm still working on the design for a complete "system", which would include what I'd call "snap-in" accessories. What I mean by that, for example, is a fixed shelf mounted high enough above the slide so that a fridge could be on the slide and fit below the shelf. By "snap in", I mean that the shelf could be installed/removed very quickly, so the Jeep could be configured for different errands easily - I don't like the idea of a system that is pretty much a permanent installation and therefore limits the usefulness of the Jeep for other jobs. Similary, I'd make the slide quickly removable, so the entire cargo compartment could be cleared of all of this stuff when all of the space is needed to haul a single large item.
I agree about the pricing of most of the commercially available slides, I don't see why a basic Jeep slide couldn't be priced in the same range as the RV slides this company makes.
Please keep the input coming, as I hear more about the features you guys would want in the ultimate cargo slide/tray system I'll keep refining my basic design to suit as many of those needs as I can.
And if you've got dimensions for what you think the perfect slide should be, please let me know so I can check the company's range of products to see if they already make something that size.
For the record: I am not an employee of the aforementioned RV company.