<p>Every indication I have, based on my experience in embedded computing is that doing something like this would require expensive equipment to get access to the platform (ICE debuggers, JTAG probes, I2C programmers, etc, etc), but I've always wondered if some ambitious hacker out there has found a way to load native code on a Blackberry device.   Anyone?</p>

<p>Edit: I'm aware of the published SDK and it's attendant restrictions.  I'm curious if anyone has attempted to get around them, and if so, how far they got.</p>

Unfortunately the official
SDK website
only seems to mention Java.  According to
wikipedia
, different versions of the BlackBerry use different processors.  Combined with the fact that RIM uses a proprietary operating system for the devices, it becomes pretty difficult to develop native code without official tools.  There is also a partial API-level security restriction which would further prohibit advanced tinkering.