Status: I bought it and now it's running as a charm under wine! 🙂
It's a risky business to do it, but it works without glitches and latency but your mileage might vary. This is my system:
*A self assembled computer with an Intel I7-4790K CPU @ 4 gHz (not overclocked) and 32 GB RAM (using only a small fraction on it. Using the CPU's GPU.
The OS is Kubuntu 16.04 with the KXStudio repo connected to it. The Toontrack programs runs under the Wine-rt windows compatibility layer, version 1.8.0. under Jack.
I usually use Carla as a a VST host, but the 64 bit version is not discovered (32 bit works), so I use Toontrack Solo a a VST host and everything works as it should. I tried the latency with the buffer size as low as 16 frames in 44.100 (0.726 sec latency) without problems, but will probably use 64 frames (2.9 msec latency) as standard during arranging , playing and tracking with my MIDI keyboard. Thanks to Jack, I can flawlessly connect anything from Superior to anything in the system and it works as it should. My DAW is Harrison Mixbus32C. It does not recognize Windows VST (it recognize Linux native VSTs) due to the previous VST licenses from Steinberg, but will probably change quite soon because Steinberg recently changed the VST license to the GPL V3.
So my conclusion is that everything works very well in a professional manner. I can easily track every ting as ordinary tracks for mixing, which is what I wanted. Anyway, it's always nice to have the plugin embedded into the DAW in stead of running it in an external host, so I hope that Toontrack follows companies/products such as Pianoteq, DiscoDSP, Loomer, Bitwig, u-he, Reaper, Harrison and others and makes a native Linux version of Superior Drummer.