Simply put: If you don't understand the terms of the licenses of the software you're using enough to interpret if what you're suggesting "is okay", you need to talk to a professional who does. If you want to seek a deal directly with the license owners, that works too but you'll still need to understand how licensing works.
Like Eliah, I'm also not a lawyer and when you're sued for following my advice, you can't say I didn't warn you. I generally agree with Eliah but I think in this case, Python is a bit different.
GPL software allows you to redistribute something as long as you provide it under the same license. In this case you would be redistributing PyQT which you can do. You'd also be distributing your product. I personally don't see why you can't do both as long as you make the source available for the GPL things you're using. You aren't integrating them into your Python, you're just using them.
To further describe what I'm talking about, if you included a library in a C project and compiled it down, you'd end up either the GPL code in your binary or you'd be creating static libraries that your code linked to (statically or dynamically). The FSF will demand you make your code available by GPL if you redistribute their protected code.
See the difference? Python's text-based distribution means the linking is pretty dynamic: There aren't static "links" to GPL code and the reference to PyQT could be substituted in a different environment. You are just using its API.
If you search for "python import gpl" you will find many, many arguments in both directions from many, many non-lawyers. This isn't a simple argument and if it did come to a lawsuit, you can be damned sure everybody on the free software side of the bench would be throwing everything at it to make sure a negative precedent was set.
So once again, you're probably not qualified to make this decision alone. Either talk to a lawyer or look at how much that would cost you and work out that it'll be cheaper just to pay for the commercial licenses.
Ignoring licensing will work out much more expensive.