Jack Audio Connection Kit + Hydrogen + Rosegarden + ZynAddSubFX + MIDI cable + new soundard with MIDI support for ALSA + (last but not least) Technics piano with MIDI out = Home studio! Did I miss anything? Oh yeah – Linux of course.
I tried the same thing about two years ago, but it was a failure. All applications were crashing very often, I got annoyed and gave up. Now it seems a lot different. Rosegarden crashed only once during today's session.
One of the quirks was the necessity of Jack recompilation. The jackd from SuSE 9.3 RPM package produced an "Illegal instruction" error. After recompiling it started working fine.
What's next? I think now I need to collect good-sounding instruments for ZynAddSubFX and try to install some LADSPA effects.