Best Tubed Preamp For A Warm, Rich Sound, Yet Still Detailed and Agile

This post is a great vehicle for people to pump their favorite preamps, which is great.  However, to actually reach your objectives, you might need a wider view.  Two points I'd make:

(1) In my humble experience, you can only get so much of the tube feel out of the preamp part of the equation.  It's there, but you get the real tubey bang for your buck out of the power amp part of the equation.  So you might consider that budget applied to a tube power amp instead.  This is where the real liquid turbiness comes in, I have found.  Or consider a full-tube integrated.  OR a tube input stage hybrid power amp with a SS output stage.  All of those may give you the full tube experience more than a preamp alone.

(2) I don't mean to say that you don't get good tubiness out of a preamp.  But if you go this way, save a substantial portion of the budget for the tubes.  The hardware is obviously important too, but if you really want to enjoy the whole experience, you'll need some nice new old stock options to play with -- Mullard, Telefunken, the usual suspects, etc.  There are some nice options at Upscale Audio, and Kevin Deal may be able to guide you to both hardware and tubes, but your mileage may vary with Kevin.

Good luck!

I was looking for exactly what the OP is looking for and I found it in the TRL The Dude, which I would rank first, and the CJ Premier 16 LS. Also the MP 1, but not with your amp. 
I currently use both the top rated 2 above and they will be my last preamps ( in different systems) 

I'd look at the Baekert Labs preamps in all price ranges they are giant killers. Bob Baekert has a patent on a new power supply, worked at CJ for years, and the many reviews of the Rhumba and Rhythm have been very positive. Plus, I understand they may be warranting their tubes for 10 years! They are Audiogon. Let Andy know you corresponded with William. Some people like them, some people don't.
As for the other brands mentioned above, many of those are in my repair shop all the time.Some are not. Why do you think people are selling them?
 I'll pass on Deal.

Misspelled name - hope the link works. dyslexia.

I agree totally with jjj666. It is extremely difficult or should I say almost impossible to determine an answer to your question without all factors taken into consideration always a concern of mine in these "best of" type threads, too many variables. I agree the amp is going to really be the thing to look at in addressing your query and the preamp should be considered in how it might mate with the amp, just MHO. What you are getting here for the most part is "what is my favorite preamp" cause some of the ones I'm familiar with listed are not what you are asking for.