Swampwalker - I hadn't thought about the used VZN100's, mostly because they're pretty rare to come see, but I do see a pair of VZN350's on AG for only $27,000!
My Berning is like yours: cryo's tubes + ERS, but no wiring/cap upgrade as of yet. As I understand it, that mod is an absolute no-brainer, so I'll be doing it sometime soon. As for the cabling - DITTO. I have heard amazing things about the Stereovox, and once I get me $$ saved up, i think I'll take a shot at using them. Allan Bhagan and a few others have spoken quite higly of these, and so far 100% of Allan's advice has been spot-on, so it's a matter of time and $$.
I also agree that all of these are lovely amplifiers that would make the "average" guy ecstatic - and that we're talking about that final "nth degree" of performance here. In fact, i heard and loved a set of Atma-Spheres in my system and loved them - I had some serious practical issues qith them (space for Mono's, the heat, exposed tubes, cost of replacing tubes, etc), otherwise I would have bought it, esp given the relatively higher supply of these. Whereas the Berning sounded as good (better in bass, and no my ear, slightly more neutral), and ran cool, cheaper upgrade, smaller, etc - but was harder to come by -i.e., so few on the used mkt - and most go for near retail when they do come along.
Never had the oppty to have the Joule's in my system, though i would have liked to try, based on everything Im reading here. The other thing to consider is that the Sonus Faber is voiced differently from the Merlin, and the value of a "warmer" sound is less of an issue - Sonus Faber uses a Berning in it's reference system, so that certaily reinforces the synergy!