Headphone amps are fetching up to around $5k, even a bit more.
My good ol' Stax amp goes for a bit under $1k nowadays and apparently it's fine. Kevin Gilmore puts out design plans for diy'ers and Headamp builds them commercially, taking in orders for 25% down, then making you wait a year or two, then you pay the rest and get the amp. Current price tag on the Blue Hawaii is $5k, AND you have to wait. Apparently, there's something like $2k in parts alone in that design, but of course one has to wonder if that's an optimal shopping spree! Woo Audio markets an old Gilmore design for about $1400 (before "upgrades") and apparently the wait is much briefer but of course it's not "the thing to get".
If Frank made an amp that could drive the Stax then I would have to seriously consider getting it but the remarkable discovery has been that even with all the advantages of having a 1.3 micron thick diaphragm, driven electrostatically, in an excellent case, hovering about an inch above the ear... even with all those inherent advantages, sound reproduction is still superior with the big speakers in the big room with room reflections and all that. Now I don't just mean bass--that was always clearly going to be better with the big drivers--but higher frequency detail as well.
The reason I think so highly of Frank's electronics is because they trump the Stax setup. Perhaps the most expensive Stax (now at a ridiculous $5k price tag), with the Blue Hawaii driving it, can compete... but I'm not holding my breath anymore for such a setup. What I have now probably sounds better already.

The other issue with the headphone market is that it can be a bit bitchy. It is such a private listening experience that when people get defensive over this or that setup, well, objectivity gets flushed down the drain even faster than in the rest of the audio market.
It's a little sad, really, because it is definitely the case that a whole bunch of people will never have any idea of how excellent music can sound because you need to have four good links in a chain: source (eg DAC), preamp, amp, and speakers. Headphones shorten that chain a bit since you don't have room problems to deal with and of course it's far less expensive to get that going. So it is probably a very natural entry point for audiophoolery and it would be nice if those novices had a Van Alstine option. It probably means more headaches for AVA, though...