That's pretty neat!
I doubt you'd need any plans since it looks pretty straight forward. Looks like they sunk 4x4's posts for the corners and line posts, attached 2x10 (or 2x12's) along the bottom, nailed 2x4's on edge on top of the 2x10's, added vertical 2x4's as supports for the upper/horizontal 2x4's, added the door and attached the wire.

I noticed they also notched and interlocked the upper 4x4 horizontal beams that are on top.

It appears to be a variation on a fruit cage. If you search on that term, you'll find lots of stuff, but annz is right - it should be easy to build something sturdy yourself to your own design. Fruit cages are largely meant to protect against birds so, if deer are your problem, you're probably best off to build something sturdier!

Have you asked at the Deer Resistance forum (aka Plants For Difficult Places)?

A recent thread there mentions a similar structure. Unfortunately, it's not a terribly busy forum.

Here is a link that might be useful: http://forums.gardenweb.com/forums/load/difficult/msg0414123912817.html?1

If I'm buying that...

I would call it raised beds surrounded by a elaborate welded wire fence. There are plenty of instructions on the net for building raised beds and for vermin resistant fencing.

We have a lot of deer as well (and raccoons). We have been very successful in keeping them out of the vegetable garden with a solar-powered electric fence. Perhaps that would be an option for you?

"overbuilt"

:-)