Hi, sorry for delay,
I have checked my "five manuals" as well, the one entitled applications has a section on Multimedia. In it Midi is well covered in an introductory sense and then some, up to you to read individual app manuals *sigh if your heart just sank so did mine* a few apps stand out first Rosegarden, second Jazz and Kmidi. how good they are remains to be seen as 7.2 is rather old, but I always liked it
The section is not short on further reading, in fact after reading chapter five which introduces MIDI from many angles through the apps which rely on it, you'll have no shortage of avenues to explore.
Unfortunately it will require a little learning on your part, but then if you're really interested in midi it should be a joy
Please post back with any success you have as I too am interested before going out and buying a midi keyboard *duck*
Oh and let this be an example of how SuSE manuals rock ie they are informative and stand the test of time rather well.