Build your own system/s. It's much cheaper, and you have much more control over the design, function, size, and whole system in general. Use the system you like as a model, and build your own custom system. You can get all the materials you need from local stores like Home depot, Lowe's, Wall-mart, Big Lots, K-mart, etc. etc. etc.. I've even seen some perfect planters/containers to use for a stacked system like the verti-grow systems at the 99 cent store. Their designed to stack offset perfectly, don't have holes in the bottoms yet (so you can place them where you want), lightproof, and cheep. Bottom line, look around, you can build your own systems better, and for way cheaper. You can even get free 1-2-3-4-5 gallon buckets from local restaurants that would normally through them out (if you just ask them for them). You cant get much cheaper than free materials.

With a little effort looking around, and building the systems yourself. You can grow 10 times more plants with the same budget, rather than spending it on per-manufactured systems.

My hydroponic Ebb and flow system
There is a pump in the reservoir down below that pumps up into the bottom of the 5 gal buckets with overflow tubes draining back into the reservoir while the pump is running. When the pump stops the water drains out of the botttom of buckets back to the reservoir system. I have several 4 inch stream rocks in the buckets for weight along with some 2 inch chunks of lava rock so the pump dosen't have to run so long to get to the baskets suspended in the bucket lid. ACE hardware helped me pick appropriate plastic connectors to attach the tubes to the buckets, and the baskets that fit in the hole I cut in the lid were purchased at a local garden shop. I was able to get the buckets for free so the fittings were the main cost and were not very expensive. The reservoir tub would be another expense, but I hapened to have one lying around. It is a 32 gallon Rubbermaid tub about half full of water with nutrients. You also see a solar panel which charges a 12 deep cycle RV battery in the shed. Also in the shed is the battery controller regulating the charge on the battery, an inverter which converts the 12V DC to 110 V AC. Plugged into the inverter outlet is a timer set to run 5 times daily for 20 min. The plant baskets sit on a 2 inch thick slab of Grodan rock wool laid on top of the rocks. It still takes about 5 min. for the water to start flowing out the overflow tubes so the plant roots are wetted about 15 min each run time. Hope this gets your design juices flowing. Have fun design your own.

Looks nice lukes52
hope you got a ladder for when those plants get about 5 feet tall. :D