If you're a BlackBerry theme developer, you've likely been waiting for RIM to release BlackBerry Theme Studio 7 since the first BlackBerry 7 devices started rolling out. As we all know, that didn't happen. Theme developers have had to use work around methods in BlackBerry Theme Studio 6 in order to offer BlackBerry 7 device owners themes and now the final word has come down from the BlackBerry Developer Team.
All plans for BlackBerry Theme Studio 7 have been cancelled due to the fact that feedback from beta testers was not good and it was clear that the quality of the tooling would not be acceptable. In addition to that, confirmation was also handed out for those looking to theme BlackBerry 10:
There will be no Theme Studio product for BlackBerry 10 and there will be no theme support in the BlackBerry 10 OS.
With BlackBerry Theme Studio 7 cancelled and no Theme Studio product being built for BlackBerry 10, what's the suggestion for BlackBerry theme developers? Build great looking apps using Cascades.
As RIM notes accurately, there are a lot of talented and creative folks out there building great looking themes who could be better served by building great user interfaces and beautiful apps. While that suggestion is entirely valid, I'm sure there are a lot of theme developers who'll still be upset at this decision, even if they never expected RIM to deliver BlackBerry Theme Studio 7.
Source: BlackBerry Dev Blog