$3500 to spend on a tube preamp....ideas?

Suggestions? Amps are Herron M1 monoblocks, Speakers Von Schweikert VR4-JR's. I borrowed a McIntosh C2300, and while it was good, it wasn't THAT much better than my Modwright 9.0 Signature. Bass was a little deeper, soundstage a bit more open, instruments more focused, but again, probably not worth $3500 to upgrade to. Also had an LS26 from ARC in my system, again, similar performance level to the C2300 and slightly more dynamic than the Modwright. With $3500 to spend, is there anything that can get me to that next level in dynamics? I am really happy with the other hardware in my system.

ideas: Herron VTSP3a, Rogue Athena
VAC Standard LE, Modwright LS36.5, Conrad Johnson Premier LS 16II, Dehavilland Mercury 3:

other options?