This is my first theme: dark and rather flat.
Tested with LMMS 1.1.3 running on Windows ... 7

Screenshots: http://imgur.com/a/SAWIQ


Modified Icons and Artwork used in this theme:

Icon Set & single design elements by Rebecca DeField
http://rebeccadefield.com/image/fulllmmsiconset

On/Off LEDs from Dark-Modern-Theme by theSynthesizza (MineCreepermann)
https://lmms.io/lsp/?action=browse&user=MineCreepermann


Trade-offs and permanent Issues:
- made the LMMS icon fully transparent (blame me!), because I find it distracting.
Especially on the title bars of very narrow ladspa effect windows.
- width/height settings of scrollbars in PianoRoll and Automation Editor seem hard-coded
- handle grips on the project notes toolbar and the expanded sidebar seem hard-coded
- project notes editor can't be properly styled (I guess)
- many more minor issues, but I think that's it. :D