Are you talking about a rack to store two rows of bikes, one on top of the other? This is our primary form of bike storage for our shop inventory, we built the racks ourselves. I would be happy to supply pics, details, measurements etc. as I was not personally the one responsible for constructing them. I'm actually not sure if it was someone from the shop or someone from the local university (like an architecture student) looking to help us out. I might even be able to find plans for them. They are constructed pretty simply, with one beam with with a section of halved, large diameter ABS pipe for the wheels to rest in and a hook at the back to hold the rear wheel. Actually, (and I'm sorry if this breaches etiquette for this listserve thingy) check out our instagram @corvallisbikes for some pics of the rack setup. It works really well! 

P.S. Apologies for the terrible style of this email. It's late and I don't want to go through and edit. Have a wonderful evening whoever reads this!

-Whit (volunteer loudmouth with the corvallis bicycle collective)