Appears that there's some buzz (four requests in less than 24 hours alone for BlackberryModem -- or six if you include mine and Guess's request) and interest in these threads: http://www.blackberryforums.com/view...20&start=0 http://www.blackberryforums.com/view...0&start=15
Demand is indeed increasing, the average number of BlackberryModem requests have gone up (About 10 requests in 5 different forums in the last 1 week alone).
If a good developer familiar with TCP/IP programming is reading this thread, they will quickly recognize that the harder part is finding the most efficient way to route data from the Blackberry to the USB port. It can be done in all sorts of arcane and silly ways (embedding packets in notes, or saving packets as disk files that javaloader copies off, etc.), but you really want a more direct routing mechanism, preferably simply opening a socket of some kind between the Blackberry and the laptop more directly -- hopefully this is already possible after the application is signed. Obviously, it's preferable to have the software on the Blackberry have direct access to the USB port if possible.
Reverse engineering using a USB sniffer would do wonders (run JAVALOADER.EXE while using a USB sniffer, for simplicity) to determine what the capabilities of transmitting the data over USB is. If the USB connection cannot act as a standard USB modem, writing a virtual modem driver with a virtual compor, or a simulated USB network card driver, if one wanted to treat the Berry like a super-slow external Ethernet adaptor rather than as a modem.
One of the first focus would probably be to determine what the options are for routing between the laptop and the Blackberry with as little overhead as possible. This one factor will probably determine the majority of the development time for a BlackberryModem program. This will go a long way to determining if writing a BlackberryModem would only take a week, or take a month, or take much longer.
If after analyzing this, and only inefficent methods of routing data between the Blackberry and the laptop is found, then a request may need to be made to RIM to allow a signed-application API to at least allow third party programs to transmit of data between the Blackberry and a laptop.