The inset shelves is a brilliant idea.
We're currently "house hunting" (I say that because housing prices around here are INSANE for what you'd get) and the ideal house would have a finished basement that I could just outfit with shelves and cabinets for my collection/craft space, but making inset shelving into a basement that wasn't 100% finished could give me a little more leeway in what we look for. To do that though, I would have to know what was going to go where before even tackling the construction, and that's more than we'd be able to do right now.
Thanks. As far as I can tell there's three difficulties with my idea beyond the 'buying a decent-size house in this economy' problem:
1.) If I ever end up wanting/needing to move, inset shelves generally lower the value of the home.
2.) It's going to be time-consuming and expensive.
3.) It locks in my collection.
The last part is the one that I'm struggling with the most. If you set your shelves for a 7" collection, it may create too much space if you shift it to 6", and definitely will be weird looking if you decide to put a 4" collection there. If you only allot so many shelves, you're also stopping the growth of that collection AND you're kind of limiting how much stuff you can get rid of as well. Would be difficult to set an area for a collection of 100 6" figures and then decide to go on a purge and end up with 20 or 30 figures. Moving things around would end up being really difficult.
BUT, I also think these problems kind of exist no matter what. Most people seem to use bookshelves/detolfs, and those aren't exactly super modular either. I'd argue they have basically all these same problems. The biggest difference is you can throw away a bookshelf and buy a different one, but altering the layout of built-in shelving will be functionally impossible.
Since I work in construction, partially in the residential sector, I've got most of the structural planning already done.
Where I live, your average basement exterior wall is a 2x4 (which is 3.5-3.75" deep) 1-2" off the concrete. On the low end, that's 4.5" of wall depth.
I can get an R20 insulation in the wall (most basements are R12 in older homes, with R20 becoming the norm now, but some people still use R12 - so this is better than MOST basements) with about 3.25" of 2lb closed cell spray foam insulation according to CAN/UCL guidelines. Technically, I would argue the R value would be higher than that, but we'll use the LTTR because that's what the government requires for some stupid reason.
That gives us a remaining depth in the wall cavity of 1.75". Fur that out with 2x2 to gain another 1.75" of depth, add in the drywall (at 1/2" for thermal barrier) and you've got a 3" deep shelf -inside- the cavity. Which is probably enough if you're a 'waiting for the bus' type of collector.
Now, if you brace in with 2x8 (might even get fancy and chamfer the outer edges), you'll have shelves that stick -into- the wall by 3" and OUT of the wall by 4.75" (little more if you drywall around the shelving, which I actually think would look better - so let's call it 5" because you can use quarter-inch drywall there).
So you've got an 8" deep shelf, in total, -practically- half in and half out of the wall, creating little alcoves every stud cavity (probably 24" on center, but you could go 16" on center or smaller if you're a madman). To me, what amounts to a series of 8" deep shelves roughly 23" wide (factoring in drywall around the studs) sounds pretty damn near fucking perfect.
And because you're recessing the shelves in the stud cavities, you can't control the shelf width beyond choosing how far apart to place your wall studs but you CAN choose how many shelves to put in on the vertical, so the height of each space is totally up to you, and you can vary it every 24" and have staggered or otherwise different-height shelves.
Start and stop within general eye level, and you leave space down below for lower TV stand/small bookcase style shelving for vehicles/playsets or what-have-you, and you can install deeper shelving above eye-level for larger items as well.
Not that anyone actually cares about ALL of that, but still. I'm really excited about the potential if/when I get around to actually doing it.