Hi Koen, The Hovland pre amp could be a start. If it will work with your amps, it might do what you desire. Warm, dynamic and a bit on the romantic side. Just one of many.
The idea is a great one. If your looking for the slam of a solid state amp and the warmth of tubes the combo. is about the only way to go. I've used the same combo. for the past six years and have been very pleased. Your selection of amps is interesting, the Levinson and Krells tend to be on opposite ends of the spectrum. The levingson is maybe closer to your taste, a bit warmer sound. I was told to try the Audio Research and the Levinson pre-amps with the Levinson amp. I was un-impressed with both, so found some other dealers armed with the knowledge that I liked the Levinson amp and Dunlavy speakers. I ended up with a totally different combo. it turned out for me the speakers drove my dissisions. There are a ton of options, but your starting point of solid state amp and tube pre-amp is sound.
It's a great combination if the pieces are well matched. I once had an Audio Research SP-6B tube pre- with a solid state amp. It was a wonderful combination. Tubes are wonderful, but you do loose some bass authority with tube amps,you have higher maintenance costs(applies to pre's as well), and you can't run low impedance speakers.(does not apply to tube pre,SS amp combo)
I matched a First Sound Presence Audio tube pre-amp with an EVo digital amp for great effect. First Sound is very very quiet, no tube haze, just that touch of life. Very important for acoustic music of any type and vocals. See Soundstage review on First Sound pre-amp, was a reviewer's choice last year.