Recommend me a tube integrated amplifier

Audio research i/50 can be had used in your budget.

Margules 240i harder to find, but possibly similar price.

A Willsenton R8 will be cheaper even with tube rolling

if you are looking for transmitter tube integrateds (211s, 845s, 805s) you might find used Line Magnetic

I have a Line Magnetic 216ia and a Rogue Audio Cronus Magnum III in a second audio system. Both can be see on my systems page. The LM Audio is designed and made in China and it’s great. A transformer went out once, but my dealer sent it to an authorized repair facility here in the USA. No problem getting it fixed. Push pull design and it punches way above its output which is like 26-32 wattts per side. The Rogue is a beast and is closer to 100wpc. I really like them both but the Rogue is made in PA and I live in OH, therefore getting it serviced shouldn’t be an issue. My vote is for Rogue Audio. I put in Gold Lion reissue tubes and NOS Sylvania in the preamp section. Sounds very sweet, detailed, organic with sufficient bass. I think there are many companies making really good tube amps. ARC, Cary, Decware and others. I would look at the reputation of the service each one offers. That’s a big part of the overall process that often gets overlooked.

@ghdprentice

I believe the Audio Research I-50 is a hybrid, not an all-tube integrated. I sold a Vsi60 a while back, and what I disliked  about it - despite its other sterling qualities - was that the sound was a bit "washed out" in the same way that Audio Research SP-11 preamplifier was back in the late '80, when I owned it. It certainly didn’t have the accurate tonal color of instruments the way they sound in any of the halls I frequented (Carnegie, The Metropolitan Opera, David B. Geffen (Avery Fisher at the time!) or the Baltimore Symphony Hall (Meyerhoff), and, if I’m on the West Coast, Davies Hall in San Francisco. The Vsi60 had some great qualities, to be sure, but tonal accuracy? I’m afraid not.

Maybe a Vsi 75 is a better candidate for an "integrated tube amp," perhaps?

Heard Synthesis amps with Audio Note, Harbeth, and ProAc speakers up at Deja Vu audio near DC and fell in love with the sound. I can't recall the model amps I heard that day but I was fortunate enough to get a good deal on a Synthesis A100 Titan from my local shop and it's a great sounding integrated amp, as I've mentioned elsewhere. 

@freediver

I had a Music Fidelity A1 for 10 years before i gave it to my sister. It’s a great little amp, but it doesn’t do what tubes do, which is to present a much more holographic presentation (assuming that that is what’s on the record). It is, however, very clear.