Or, to put it another way, to the guest, the hosts folders aren't local. Likewise for the host, with regard to the guest's folders.
Come to think of it, it's actually quite dropbox-like in operation, and has performance to match as a result. But, hell, if you can do better, go right ahead.
That's only step one, though. Start ordering disks when you start your first production run of hardware. Order direct from manufacturer, and from as many suppliers as possible, so you get disks from as many batches as possible. Then, continue placing frequent, but small, orders from whoever can get you the disks the cheapest; it may work out that you can get volume pricing from the manufacturer by telling them "I'm going to need X disks over all and am willing to pay for them up front, but I need them shipped (X/52) per week from current stock at the time of shipping, don't set aside my disks out of the current batch to ship at a future date".
It's a bit more labor, but compare serial numbers and attempt to color code by batch. Use colored dot stickers for this. When fetching drives for an installation, try and get an even distribution of colors, so you don't have an excess of drives from any given batch, and always record who has which drives, so if you start getting failure reports that indicate a bad batch, you can proactively alert the customers who have those drives that it might be a good idea to have you swap them even if they still appear to be functioning.
All of that drives up the cost, of course. I'm not going to sit here and to the math to figure out what the cost would be, as there are simply too many assumptions and I have too little time, but if you've nothing better to do and don't mind making a couple dozen, likely provably wrong, assumptions, you can have at it.
My old laptop, which crapped out last week, had no trouble keeping up with me, I never found myself waiting for it, and I'm not a gamer, so when I ended up with a new machine that was roughly 20% faster, I decided to enable FileVault on it. I figured, worst case, it'll slow the new laptop back down to what I'm used to. And now, if my laptop is every analyzed by a law enforcement agency, I'll just become another bit of noise the NSA has to filter out.
And Apple has made FileVault a "checked by default" option when setting up a new Mac, so the same class of user who would end up with every toolbar and fake anti-virus in Windows (e.g. average or below average) will have FileVault enabled on their Mac. if Microsoft takes the same route (I haven't installed Windows 8 or newer recently, so I don't know, they may have already), we're looking at something like 2/3 of computer users with file encryption enabled by default, without even knowing it, and some portion of the remaining 1/3 who enabled it purposefully.
I can imagine the high-ranking NSA official who instituted the "record all encrypted data we find" policy, on the basis that only people with something to hide would bother, is sweating right now, as his colleagues are starting to realize he's just made all of their jobs that much more difficult; it has come to pass that only a handful of criminals, and no known terrorists, have made effective use of encryption, but they're still having to sift through all of the metadata recorded along with all of that encrypted data.
Also, before someone else makes the joke: "only criminals, security agencies, and banks" is redundant.
which allows google to extort more license fees
That said, I do wonder what some of these implementations do when a user tries to print the page. Does the print view also lazy load, or does it load all of the content because, well, you know, it can't pop it on the printed page when you go to view it; it has to be there for printing.
In short, I guess I'm asking if you've ever tried the print view as a solution for your use-case, as it would have to be *severely* broken (in which case, let the site operators know, maybe they care enough to fix it) to not do pretty much exactly what you want. And if they're doing lazy loading and don't have a print view, well, then they're just asshole developers; in which case, you should probably let them know that, as well.