Stackable Vivaria?

[Yemeyana]

I'm looking to get a fairly large collection of herps and small mammals for the cabin at the side of my house (don't worry - heating issues will be addressed separately!) and I've worked out that the floor space I can take up is 4'x2'.

For height, I should have 12" of nothing (no vivarium on floor level) then a 16" high, a 12" high (for inverts), then two more 16" highs.

It may be necessary to have front- and side-facing vivs, as in the back of a 2' long against a 2' wide one (depending on how I work out the animals' cage requirements) as I assume a corn snake would not appreciate a 1'x4' or a 2'x2', and reaching into a viv 1'x2' from the narrow end won't be fun!

So on to the question: what's the best way to go about this in terms of the cages? I bought a Vivexotic for my hognose, but there's a lot of hassle involved in the construction, and I'd rather avoid that if possible.
The best way I see would be either a specially-made vivarium rack system, or a strong shelving unit.

(PS - I'm not talking about cramming animals into small enclosures. I'm talking about cramming adequate enclosures into the space I have.)