In keeping with my budget-friendly lifestyle, that stand was purchased for $250 used off of craigslist. I've found some really nice furniture that way - I find the key is to look for ads from people in nice neighborhoods, oftentimes they just bought some new stuff and just want to get rid of the old stuff and aren't looking to make maximum dollar on the resale. New furniture is SO expensive, used is the way to go. e.g. got a really nice dark wood dining room table set + six chairs for $150 off some young married couple who had just upgraded!
I have no idea what brand it is or where to get it, unfortunately. It's actually a really nice stand and comparable in build quality to $1000-ish stands like BDI or Studiotech stuff (I've checked them out). Real solid wood, no cheap particle board panels, and it has optional inserts for the doors with either glass (what I use) or black speaker-cloth mesh.
The only thing it doesn't have is the fancy a/v-focused extras like cable management and sliding back panels that you get with a BDI or similar stand. The back panel is a single piece of heavy-duty cardboard (not like currogated cardboard from a box, but the thick rigid stuff like what clipboards are sometimes made of). There are two big vertical channel slots cut into the backing to allow cables to flow in and out of the two a/v compartment areas.
Don't know about ventilation but have never had a problem tripping the protection circuits of my older Sony DA555ES and my newer Denon AVR 2105. I've heard the Onkyo's run hot, though, and the 805 is a beast, so if I had something like that I'd probably want to install a couple of fans in the back for ventilation (and maybe switch to the speaker cloth so some air can get in the front).
I think it would also be a tight squeeze, assuming the 805 is a little meatier than the standard AV receiver. My AVR 2105 has about an inch of room side-to-side and just enough room (maybe 2-3 inches in the back) to manage all the cables and plugs in the back. I had thought about trying to find a used Denon 4800 or 4802 (which sometimes go for under $400 on ebay) but it wouldn't fit, since they are longer and a little wider.