I put an update of RoboPlay for download here, which includes the playback of MIDI using the wave table (you do need a turboR for this) or FM. Still not perfect but a lot of MIDI files already play quite well
Here a video showing some examples of current status, played in OpenMSX 16.0.
SCC Musixx support added as well, see video for some examples.
Binaries of latest version can still be downloaded from this location.
Also updated the RoboPlay Starter pack with a number of SCC based songs, which you can find here.
Currently the following file formats are supported:
For OPL4:
SOP: Note OPL3 Music Sequencer
D00: EdLib packed module
DRO: DOSBox Raw OPL v0.1 and v2.0
RAW: Rdos Adlib Capture
MOD: Amiga Module (up to 24 channels)
VGM: Video Game Music
IMF: iD Software Music Format (for .WLF extension 700Hz replay is used)
Sure, should not be a big change I think. Currently you can already create a .m3u file and move to the files listed in it one by one (or use the /R option to randomize). But indeed, playing with a wildcard sounds like a good option.
It was actually also tested on a 1.0 moonsound and there it looked to work. Thanks for the test. 
