Not answering the real question but we have a lot of little wxPython GUIs driving big engineering design software suites at the advanced nuclear design company I work at. Engineers (mechanical, nuclear, etc.) can grasp it fairly quickly, get their knobs on the screen, and be back to doing their mechanical and nuclear engineering. We got started because the original python guy (me) learned it from a grad student in 2005 via the excellent wx docs and demos collection of examples. Works great and we recently went all Python 3.

I realized it's a great tool for quick prototyping, especially internal software, but I was wondering if anybody took it beyond that.

Not that I know of. Here is a list from the wxPython homepage: https://wiki.wxpython.org/wxPythonPit%20Apps

As you can see much of the list is either 'toy' applications or older applications that haven't been updated for ages.

Chandler is on that list! That's the failed PIM desktop software that Mitch Kapor financed as a hobby project and which was the subject of the book "Dreaming in Code"by Scott Rosenberg. Terrific book, shame about the software.

Matches my experience very well. A few jobs ago I was developing in house apps using WxPython at a civil engineering company.

It's big in music and math for some reason; Maxima's main front-end is wx, GNUplot uses it, and a whole bunch of sequencers use it. Also the vanilla eMule and BitTorrent gui clients.

Not sure if you meant only in wxPython or wxWidgets as well, but a big one that is mainly in C++ but also provides Python scripting is KiCad: http://kicad.org

I read a while ago that Dropbox desktop clients are written in wxPython, and maybe on all of Windows, MacOS, and Linux. Don't have a citation right now.