For my ECL500 class, Carl Desautels and I created a blackberry drawing app, dubbed drawsy. The project originally started off as an attempt to port processing over the blackberry, but in doing so, numerous problems arose. The processing code was littered with java.awt calls aswell as java.swing calls. It became too much of a monumental task to port over in the time we had. We decided on a reasonable compromise, create our own.
The easiest way to acheive what we wanted was to draw using bitmaps. Although this sounds weird, it actually worked out quite nicely. We basically decided to draw each time a touch or scrollwheel event happened. We added the functionality to change colours (42 colours to be exact), change the brush size, clear the screen, and set the brush to a marker mode (made the colours displayed translucent, and the longer you pushed, the darker the colours would get.) Although the app does what we set out to do, there is still much more we want done. The ability to save your sketch, set any picture as the background and draw on it, and make some performance enhancements. There is also numerous small bugs that need ironing out.
In the meantime, take this extremely poor quality video of the app.