What, no class D bashing? Have we finally arrived?
IMO Jwarmbrand's suggestion is more to the point. With class D the question isn't so much tube or solid state it's getting as much off the grid as possible. My Nuforce SE's took on a much fuller and more quiet presentation when I replaced an upgraded A I 3A with my current battery powered pre.
Unfortunately the resolution and transparency offered by many class D designs is often misdiagnosed as sterile or forward. My system benefited greatly from a new metal clad conduit, dedicated AC line, and from mass loading the SE's casework with some DIY sandbags. Addressing the vibration and the AC should be seriously considered before applying the tube preamp band aid.
All my vacuum tubes have now migrated from the back end to the front. The output section of my ModWright/Denon player is tube driven as is my FM tuner. There is no substitution for the effect tubes can have on an audio system and I haven't heard any solid state or class D product that sounds like tubes. Likewise, I haven't heard a tube system that sounds like a well executed class D system.
I have heard noise at low listening levels from the four tube preamps I auditioned in my system. Not that big of a deal and the noise wasn't an issue at louder levels. I think there is a battery powered tube preamp, Dodd?