which tube mono blocks?

Well, you could try out the VTL MB 450s. They are very good, and very powerful. Used they run around $4,500. (I doubt the MB-125's (100 wpc) would work very well, as they are not powerful enough, IMHO.)

(You are on the right track though, as you will need very powerful amps with those speakers. You might want to stick with solid state amps, as tube amps this powerful tend to be somewhat expensive, and generate a fair amount of heat. And, can cost a bundle to retube!)

11-19-08: Detlof
Atma-Sphere Music Amplifier MA-2 Mk. III

Hasn't Ralph "Atmasphere" Karsten posted around here that all OTL amps prefer to work into higher impedance loads? The higher, the better, due to distortion issues.(did I get this right?)

I'm pretty sure he has recommended using Speltz Zero's impedance-matching external transformers to raise speakers below 4 ohms up to a more workable range.

Anyway, back to the original question. Jtwrace's Final 1000i's are actually rated in the 3 ohm range according to the website:

The simplicity of the new Inverter Technology™ design insures speaker impedance will remain well above 4 ohms across the entire frequency spectrum for the smaller speakers and above 3 Ohm for the larger models.

The 1000i are the largest panels they make and Dick Olsher's 2007 review states that they actually dip into the 2 ohm range.

Ronald Buining, one of Final's designers and engineers, explained that since the treble is emitted by a narrow strip, the speaker's capacitive loading is reduced. And it is primarily the reduced capacitance that is responsible for the impedance magnitude remaining at about 2 Ohm around 20kHz for the 1000i.

If that low of impedance and high power are a must, then think about Wolcott amplifiers. They are famous for driving the largest Soundlab A-1 panels without breaking a sweat.

Otherwise, get some Zero's and use the 3x or 4x multiplier taps, your tube amp choices will open exponentially.

I have a pair of Acoustat Spectra 33's and when in use they are powered by VTL 300 Deluxe Mono Blocks. Plenty of power with lots of finesse.

I suspect none of you who have responded so far have heard the Coincident 211 Dragon monoamps - 80w/channel . They are superb and are a must audition .

While I am partial to NAT Audio since my firm also imports the line, I would like to suggest doing some research on this incredible line and more specifically on the model called "Generators" that can run any loudspeaker from 2ohm up to 16ohm and is 180wpc into 8ohm and 240wpc into 4ohm. They are within the price range of what you're looking to spend.
www.nataudio.com and www.musicalsounds.us

Good luck