Best tube preamplifier for under $15k

With a 15k budget, I would seriously consider the Vinnie Rossi L2 Signature Preamplifier.  Perhaps a demo/used can be had for less than your budget.

+1 for the Vinnie Rossi
Have loved Vinnie’s work since Red a Wine Audio. He really knows what music sounds like and is able to infuse that.
My other very high recommendation is Audible Illusions.
A rare company that has specialized in only making preamps for decades. They have kept improving and have been listed in TAS at “the best at any price” forever. I happily live with mine. Ultra neutral with only one tube pre channel in single ended with an external power supply. 

I listened to a number of tube preamps in the $7K to $10K range ($15K is outside of my budget) and landed on Balanced Audio Technology (BAT).  What a fantastic design philosophy, and sonically it delivers a phenomenal soundstage with imaging that is a mile deep.  Sonically I find that everything about it is, well, just right.  The VK-33SE is $10K but you can go up from there to the VK-53SE at $15K.
They do operate with a remote, which comes in the box.  A very well made, all aluminum remote that is not cluttered but has just the right amount of function controls.  A very cool feature on the remote is a "fade mute" function.  One touch button and the volume fades away rather than a hard mute (though there is a total mute function, too).  You only realize how wonderful that feature is once you have it.  The preamp features are great, but it's the sound quality that got me.  I am surprised not to have seen others mention the BAT brand.  It's very well reviewed and regarded in this industry.

Don Sachs new custom line pre.  It bested my Pass X-22, ARC-6se, and PSA-BHK... in my system.  Your mileage may vary. 

@keithr, Since you are coming from a Music First Audio TVC preamp, you will value a preamp that's not colored or voiced I guess. Shindo, Audio Note, CJ and the likes are all very voiced products. They have a strong house sound. 
At least I have used them all and found it that way. If you want a really good preamp without voicing and full range, direct sound, check out Wavac PR-Z1 or PRT-1. Fast, natural, glowing sound without voicing.