License

[fabioz]

In the comment related to the license, it's written:

License: GPLv2 or any later — due to use of PyQt4.

Actually, your own license doesn't really have to depend on the PyQt license as you're not distributing PyQt with your product -- yes, it's a dependency, but as you're not distributing it, you can use any license you want (also, keep in mind that even PyQt has a commercial license, so, if you just distribute as GPL, you'd be cutting out users of that commercial license).

So, my suggestion (if your issue is only due to the use of PyQt4 license) would be dual-licensing GPL and another such as MIT or LGPL (MIT can actually be bundled with any product with any license).

As a note, I was thinking about porting color-palette to use PySide (which has an LGPL license), but with your current license, the port would need to be GPL even without using PyQt4.

[portnov]

Well, I'm hardly a licensing specialist... It is not even easy to distinguish GPL vs LGPL :)
I'm not sure how to do dual-licensing correctly either.
Also,

as you're not distributing PyQt with your product

Actually, PyQt builds are included into installers for Windows: it would be too much to ask windows user to install pyqt separately.