We looked at the anthropologie door knobs for our house too (the regular glass not bubble glass). The problem was they don't come with the parts that actually make the door work- they are just dummy knobs. If you want the knob to actually turn and be functional, you need to get the parts for that and attach the knobs to them. The doors will just be standard, you don't need custom doors, but it is the door knob part that you need.

Something like this in the appropriate color: http://www.ebay.com/itm/Install-Spindle-type-Glass-knobs-in-any-pre-dilled-Door-/400004624105?pt=Architectural_Garden&hash=item5d22222ee9#ht_803wt_1268

The kits for the door knobs to make them work cost as much, if not more, than the door knob. We didn't end up using the anthropologie ones because we found some antique glass ones, but the ones we used also were just dummy knobs and needed the knob parts.

Because we needed 83 door knobs, it would have cost us almost $2500 to get the knob kits. We ended up buying $8 builder-grade door knobs from Home Depot, disassembling them and stripping them for parts and then attaching the antique glass door knobs we bought to them (my father-in-law did this for us because he is handy... I would not have been able to do it).

83 doorknobs---wow!!! I think I only need 6! (I would only do them on the first floor.) :)

Here are two reviews from anthro that explain what's required to get these doorknobs to work...

Review #1
Here's what we had to do to make these work. First - we had to order custom doors with specially cut "antique" style holes for the handle. this is basically a 1/2" hole with a connecting shaft through to the frame. Second - you'll need a "standard tubular back set conversion latch" that will fit a square spindle. We got some from "house of antique hardware" online for about $10 each. Lastly, the square spindle that comes with the knob is too short for a standard door width. You will need to get one that is about 1/2" longer to get the knobs to securely attach. This knob needed a course thread. We got ours from Weeks in Portland Oregon for about $8. So all in all, our new knobs cost us: Custom Door slab: $60, retro latch kit: $10, longer square spindle: $8

Review #2
These doorknobs are gorgeous, but they don't play nice with many modern doors. Modern doors have a bigger hole around where the rosette plate goes, so there's nowhere to screw these rosettes in. Also, these knobs come with NO HARDWARE at all (no screws, no latch), and your existing modern latches will not fit the older square spindle in these glass knobs.
If you have modern hollow doors, here's what you'll need to make these work for you. I've included links to buy the items, since they can be hard to find:
1. retro door latch guts (http://houseofantiquehardware.com/s.nl/it.A/id.626/.f?sc=10&category=16)
2. door "bore insert" to have something to screw the rosette into (http://www.rejuvenation.com/fixshow5845/templates/selection.phtml)
3. screws (I bought 1/2 inch #5 flathead wood screws in a satin nickel finish at Ace Hardware. They're like 27 cents apiece. Not worth paying for shipping on these, just buy them in person.)

I'm wondering if this is something I would need to mention to my builder now? Or can we figure it out down the road?

I'd ask your builder. We got charged by our builder for the extra labor involved in making the door knobs work and all they had to do was install them (it took more work b/c the set screw had to be tightened just so in order for the knobs to turn properly).

What you would need to do if the rosette plate is too small is either get a door that is not pre-drilled and then get the door hardware kits I would think.

The easiest way to do it, and cheapest, if you can, would probably be to do something like we did and just use the knob part itself and buy your own door knob so you wouldn't need custom doors and all those parts. Take the door knob you buy apart, then attach the new door knob to the rosette you have. You will need to be handy or your builder will need to be willing to do that for you.

If your builder has to assemble all of those, drill into the door for the insert, etc. and you need to get custom doors, even your six knobs might become pretty expensive.

Thank you for the advice! My husband and I are very handy--I think we can handle that now that we have a rough idea of how to do it! :)