Tube Preamps with Bass?

It's gonna be hard finding one to audition but you should try a Supratek. Your search will be over.

I use the First Sound with a Pass 150. There is a slight impedance mismatch between these two components, which may limit bass performance a little, though I can not be sure of that. But I do get excellent bass and I think the First Sound in general is a superb preamp for bass. Superb.

I 2nd Lugnut's response. I use my supratek with an Air-Tight ATM-2 tube amp - I get all the bass response I'll ever need. Alternatively, you could give HOVLAND a try.

Mcintosh C2200

Aronov Audio LS-9000 tube preamp together with top of the line Mapleshade power cord (and, presumably any other great power cord) has tremendous bass slam, along with natural, musical sound throughout the entire audible range. See review in soundstage.com for introduction to Aronov line.
If you already have your ideal amp, then EVS Ultimate Attenuators (from tweakaudio.com) which attach directly into RCA input jacks of amp eliminate one interconnect, and allow all that your amp is capable of in bass slam, weight, and dynamics. Used in single source system, such as one where you listen only to CD's. Retail is $350, although I got mine for less as a used item on Audiogon.