And please don't tell me it's not possible.
Well i would take a look at wx.ButtonPanel, it does the things you want, it can act like an awesome toolbar as well as having an image/gradient as the background. I would love to attach some code as an example but my computer has decided it really dosent want to co-operate right now.
But have a look at the wxPython demo. That shows it with a gradient, its soposedly not that hard to change that to a bmp.
Well the bitmap i wanted to use was a gradient.
Heeh, wxDemo is a good friend, it have got alot of examples and infact, though little complex in some cases, but they help alot