High end amp - my last step

I would like some opinions on buying an amp.

I have some unusual constraints, but a pretty healthy budget.

The constraints:

1) I'm in the UK - 230/240 volts must be available - even if a second hand model has to be sent back to the manufacturer.

2) The amp / amps must live in a space in a well ventilated cabinet, open back and full grill to front plus much ventilation above and below. Space is about 24 inches wide, 30 inches deep and 14 inches high for a mono. Height can be doubled for a stereo amp, e.g. a VTL s-400 will fit but Seigfried Monos will not. Heat should *not* been seen as much of an issue, size should - eg a Krell MRA would drop straight through the floor into the utility room.

3) Power should be enough for a dynamic sound in my 89dB efficient Sophias, but just enough is good enough as these will probably be replaced in the future.

4) Aggravation free, long warranties are good and local dealer support good too - so would demonstrations.

I don't mind tubes, solid state or hybrids. I mostly listen to jazz, indie and pop - actually anything apart from opera.

The budget:

$30,000 - I will consider second hand and I will consider cheaper if I can find it :o)

My own suggestions:

VTL s-400 or 450 monos. (UK distributor - DCS - is less than 5 miles away and will be able to demo at home during April)
Lamm 1.2 ref (No representation in uk :-( )
Audio Research 600's
Dartzeel - (My Wilson dealer carries them, and they look like they won't break, I should get a demo)
Other ideas MBL, Boulder, CAT

I'm not in a rush, probably want to buy in June, but I want to sort out some listening sessions. I *do not* intend to ever buy another amp, so it should be good for (or servicable) for next 20 years!