While I haven't heard solid state amps that sound quite like better low-powered tube amps, that is not to say that some remain nice choices. I liked the First Watt J-2 amp I had in my system for a couple of weeks. I have also heard some nice systems powered by Ayre amps and Rowland amps. These days, solid state amps DO NOT sound harsh or grainy or unpleasant as they did in the past. Rather, they sound a touch lifeless unless played loudly, and are not quite as engaging (one's interest in the music tends to wane earlier). There can also be a slightly artificial "edge" to the attack of notes with solid state (also the case with many high-powered tube amps), but some people like that sound.
A local dealership that sells only tube amplification has a Parasound JC-1 amp. I asked the owner why he has that amp and he said that he heard that it is one of the better sounding solid state amps. He uses it for demonstrations where customers want to hear a direct comparison between tubes and solid state. In other words, he uses the solid state amp to make sales of tube amps. It works.