I know 4.2 is still in beta and this may be already being included but I think options to change the colour of the vertical strip and also the colours of the background and selected item would be good, maybe even different coloured text in a menu while you're at it.
I think he means the gradient color. For example I want to emulate the office 2003 or the office 97 style. It would be a nice thing to change the stripe color directly from the program. This can also help one to obtain contrast if the color of the menu stripe is the same as the icon.
None are more hopelessly enslaved than those who falsely believe they are free. (Goethe)
Also, if you look at the office style menu thread then you will notice that the highlighted menu item is not the same as it is with the pb imagemenu, on mine the pb menu highlight is quite a dark blue whereas with the office style menu it is the plale blue you get when you don't use an imagemenu. (hope that makes sense).
Basically, I think more control over the colours would be useful, maybe with defaults that use the system colours.