I'm aware of the existence of that set. The problem with that set (and, from the look of the price, also the one that Robert linked to) is that it includes the Appendices on DVD carried over from the original extended DVDs. I'm not really interested in paying a large amount of money for carryover extras which I already own. I want the extended movies and maybe the commentaries to go with it and nothing else so that the price is cheaper. I'm going to keep the DVDs, so it's irritating to pay so much when all I really need is the extended movies in HD. I'd pay maybe $30 or $40 total for them, but the price of the box set is clearly higher because they're including the extras I already have.
Unfortunately, that's not how these things generally work. They don't do ala carte. And as the disc market shrinks, you're probably going to get even less options than before.
As it is, they already offer more options for this series (from multiple dips) than most others, so don't hold your breath on getting exactly what you want at the price you want and nothing more.
Your best bet might be for one of these boxsets to hit some bargain bin or clearance sale somewhere so it's cheap enough for you.
Alternatively, you could just go for the digital version whenever they go on sale...
_Man_