Used Preamp for $2000 to $3000

BAT VK-30 or stretch a bit and get a VK50. Both preamps are available here on the 'Gon (used) and in your price range. Can't go wrong with BAT

Rogue magnum 99 or McIntosh C2200. Both tube preamps with great dynamics, detail and realism. I've used both with VonSchweikert VR4JRs and they make the VS speakers sing. I currently have the C2200 and would not replace it for anything at any price.

Modwright ... 9.0 SE

http://www.modwright.com/products/index.php?product_id=21

Dan is a great man.

So many choices - you will get many opinions here. There probably will be many great combos.

I will only chant that:

"I LOVE A TUBED LINESTAGE" With or without a tubed amp. It made me a believer in about 30 seconds. I'm running a Levinson 23.5 and it brought it to life.

Happy, happy, horse

For that price you can get a new Modwright SWL 9.0 SE (with Bybee and Blackgate upgrades) hybrid linestage.
It is incredibly open, quiet, transparent, dynamic and three dimensional. Rivals linestages costing far more. Check out the reviews at "6 Moons" and "Enjoy The Music."
Both writers bought the review unit.
I suggest the Tung Sol over the Jan Philips tubes.

How about Audio Research? Wonderfully musical gear and great upgrade paths.