Ian, for what you're doing, I'm not sure if the new DPAs would be "better" or not, but they are both (a) Larger and (B) More expensive. They'll be $3600 (or the Euro conversion) new for the set with the smaller-sized cardiod caps; the larger, cheaper caps won't work for stealth. And even the "compact" bodies are larger than the 402x series, though they are tiny.
I hadn't noticed the big difference in length between the MMC 40xx and the MMC 20xx. The latter are more than twice the length of the former, so yeah, that makes them significantly less appealing. The MMC 4011s are about €1150 each here.
If all things were held truly equal, which they never are, it sounds like Schoeps CCM4s or CCM41s (probably better) and a DR-100mkII or PMD661 would fit your requirements - stealthy, sounds amazing, easy to set up, no custom U.S. gear required. The CCM41s (the compact hypercardiods) will sound beautiful wherever you are, are small, are easy to setup, etc. But they aren't cheap. At all.
Your reasoning has a lot of appeal: universally acclaimed mics, very small, no fuss and no custom gear needed.
I really do want to avoid the extra point of failure that extra pre-amps/adapters/battery boxes, etc. would introduce. U.S. manufactured boutique gear would also bring expensive postage in both directions if mods or repairs were required, plus the chance of getting hit multiple times with customs duties when those border guys fail to realise I already own the thing that has been sent to me. All in all, a hassle best avoided if possible.
There's very little that can go wrong with the set-up you describe, apart from severe damage to one's wallet and the resulting deterioration of one's matrimonial relationship. The CCM 41V is €2100 here. Ouch.
At some of the gigs I go to, beer occasionally goes flying overhead, dousing everyone and everything under it. When that happens now, I dab my 4060s and shrug it off as par for the course. With 2 of those CCM 41Vs, the necessary cables and a new recorder, I'd be carrying 5 grand's worth of gear on me. Like everything, though, I suppose I'd get used to the idea.
A couple of questions about the CCMs, since we're back on the subject. Would you recommend the verticals (the CCM 4V) over the standard (CCM 4)? I'd imagine that's better for my purposes, but that's just an educated guess, whereas you would know for sure.
Also, there are LG and UG versions, but as usual, I can't find anything on Schoeps site that tells me what those abbreviations mean. What's the difference? The price is the same for both.
One final point on the CCMs. I know I'd lose the ability to change caps, but I'm wondering how much of a disadvantage this would be in practice. How many tapers actually decide whether to take wides, regulars or hypers to a particular show? Does the question even have any relevance in the context of stealth taping from pre-assigned seats? For stack taping, I'd imagine the hypers are always what you'd want to use. Do you agree?
Beyond that, I'd still look back to used 4021s, so long as they were in excellent condition.
New 4021s are €1539 here, just as a comparison for you.
Finally, on the question of the recorder, that DR-100 MK II does look lovely. I'm curious whether there's anything the PMD-661 offers that the much cheaper DR-100 MK II doesn't. That's something I can research on my own, though. These mics, on the other hand, are complex enough that I'm likely to make expensive mistakes if I don't first pick the brains of the experts.
Again, thanks to everyone for all of the replies. I'm struggling to reply to all of the good feedback I've had. Page, I'll get to you and your PM this evening, if I don't fall asleep at the computer as I did last night!
Cheers, everyone.