Okay, it sorta works (found another 4.2 BlackBerry I could temporarily use).
- Requires OS 4.2, so not compatible with older Bluetooth BlackBerry models;
- Somewhat unstable (hitting Q key causes it to crash);
- No splitscreen (Cannot type at the same time others are typing);
- Backscroll behaves weird/buggy;
- Too high-latency;
- Crashes a lot.
The fact that I am able to do this at all, does prove the premise that unactivated BlackBerries can use Bluetooth to communicate with each other. In other words, somebody needs to recreate this application using RIM API's rather than J2ME API's, to get around these limitations. Possibly use a continuous two-way SPP (serial) connection to eliminate latency, as well. Mesh networking to relay between more than 2 BlackBerries, would be needed.
In other words: It can be done. But this application isn't good enough. Somebody needs to reinvent this.
Another possible use: Internet sharing of multiple BlackBerries on one data plan, as long as all BlackBerries are reasonably close together
. More technical info: For example, it may also be a method to allow 3 people to share one BlackBerry for a chat conference connection since in theory it's possible to have 3 concurrent IM logins (MSN/Google/Yahoo/AIM or whatever) over the same wireless connection. Own two cellphones but one cellphone plan -- and both of you can be logged onto two separate IM accounts (using Bluetooth as a bridge between these two cellphones). Internet sharing over Bluetooth, essentially! Obviously, applications would need to be specially designed to support TCP/IP proxy over Bluetooth, since it would not be normally possible to hook the OS's own TCP/IP stack. So no BlackBerry email, no BlackBerry browser on the unactivated phone, but Bluetooth isn't crippled if you don't have a SIM card, and this software proves it's possible to communicate between two BlackBerries (one activated, and one not activated), so the activated BlackBerry simply has to become the "proxy server" to the unactivated BlackBerry. And that the BES policy allows it.