There is a simple theming system which allows you to change the basic look of iQSynth.
To create your own theme you need, 3 images and an info text file in a sub folder of the ~/iQSynth/themes.
The images MUST be png format and 1920x1080 at this time. The info file contents is self-explanatory, copy from the 'DEFAULT' theme folder and edit as required.
There is a GIMP .xcf project file available (.tar.gz) for download which includes the 'DEFAULT' style and some guide layers.
If you'd like to share your custom theme on this site please email firstname.lastname@example.org for consideration. If this takes off, I'll create a user submission form.
NOTE: The 'DEFAULT' theme folder is reset on each run of iQSynth, any changes to the files in the 'DEFAULT' theme folder will be overwritten.