As far as Windows is concerned, libcouchbase is prepackaged with the extension, so it’s not a problem.
As OS X is a fairly homogenous platform you can get away with prebuilding those things as well. You already use PyQt which is itself much more difficult to build and deploy for multiple platforms - however PyQt ships prebuilt binaries for this purpose.
You can do the same with the Couchbase Python module.
If you tell me a bit more in detail what you’re working with (i.e. platform specifics, mode of deployment), I can give you more detailed information.
In the meantime, read up on Python’s “bdist” target (via setup.py) and have a look here: