Looking for 50-100 watts of Tube Power (give or take) for my JBL 4349s

A used Rogers High Fidelity integrated might show up close to your price range.  Class A, 112 watts.  
 

Many ways to go. Are you committed to separates? 

Better places to spend your HiFi $ than that.

The AR 50 INT should do the job. You mention

reliability to be important. Tubes do not equal reliability.

I use a Pass INT 25, rated to 65wpc, which sadly I must sell due to new speakers.

I use a ANK 4.1x DAC which has tubes.  

My Pass can be had for $4k. Not a scratch on it, more reliable than

anything on your list and only 4 years old. 

@rischa 

Truth be told, I have not heard a tube power amplifier. All the tube setups I have heard in showrooms, audio shows, and friends’ are all integrated. With the exception of lab12 pre1 and suara that I auditioned alongside Lab12 Integre4. The Suara is excellent power amplifier btw and do consider auditioning it if possible. Looking through audiogon earlier there is currently a BAT V56SE for sale. I’ve heard BAT’s higher end stuff and they were certainly impressive.

I would not assume more watts automatically mean bigger sound. My Cobra produces less than half the power of my Lab12, yet it throws bigger more expansive sound. 

Ayon  spirit 3 ,best build quality by far for the money ,uses all Lundahl  transformers and chokes which is the heart of any tube amplifier ,Mundorf capacitors , a machined aluminum case,not sheet metal 

allGold Copper tube sockets, not cheap brass like most ,and microprocessor controlled , it automatically adjusts each kt150 tube , if a tube goes bad a led light comes on you just replace that one tube ,then hit a button , it then recalibrates all the tubes  made in Austria .and very powerful and detailed.

Might want to give the PrimaLuna Evo series a look as well. Very well made in China using above average components with excellent performance and top notch build quality. They can use a wide range of power tubes allowing you to get the output and sound you prefer. New ones fit in your price range. Upscale Audio is the US distributor and also the repair point. I also highly  recommend Vincent Audio if you are interested in hybrid designs with tubes in the pre section. Also made in China to the strict standards of their German designers. My SV-237MK is the piece of gear that never gets sold because It's my fallback between purchases. Every time I put it back in my system, I wonder why I switched because it sounds so good, but then the next shiny new thing catches my eye! They offer hybrid preamps, amps, and integrated amps. Available through Upscale and Audio Advisor.