Convenient off the shelf rack solutions

In the last few weeks, I've been working on another house remodel (the basement this time) and I am now ready to start really expanding the fish room. I'm looking for interesting rack+tank combinations that maximize water to space ratio. So what combinations have you guys found that work really well for stocking up tanks?

Some I've heard of/tried:
40 breeder on a 18x36 1000lbs commercial rack (fits like a glove)
20 long on a 14x36 wire frame rack (leaves 1.5" on either side free for cables or filters)
18x18 cubes on a 18x24 wire frame rack (leaves 2" on either side, can't use 18x18 racks cause the poles make it an effective 14x18)

Some solutions that are kind of blah:
10 gallons x 4 on a 48"x24" commercial rack (4 wasted inches in the back, and about 8 inches on the sides)
10 gallons on a 24x14 wire rack (makes for an unstable rack... plus wastes 4 inches along the length of the tank (fits nicely with the poles tho)

What are your experiences building out racks? And do share some about plumbing too! I'm really inspired by jubs's [You must be registered and logged in to see this link.] that he shared earlier and will probably copy that in my setup this time around!

Also, if anyone has a line on a nice off the shelf rack that's 48x12 (for 33 long tanks) let me know!!!

How many does it need to hold? I sell metal tank stands that hold 2 of them.

2 of them. I'd like to keep the bottom one at least 20" off the ground for easy gravity drainage.