I don't know anything about lead times, but the TINI isn't expensive compared to the rocketport stuff.

The 512k versions are $50 qty. 1, and all you need is a 72pin Dimm socket. Details here, but in short there's 10Base-T and 2 serial ports, one with RS232 levels, one TTL. It also has a CAN interface, which may be handy for automotive applications, and a 1-wire interface if you want more sensors.

I'm no Java programmer, but from a hardware standpoint this seems nearly ideal, to be able to connect a bunch of IO to the ethernet port of the empeg.

I could see a board with a ELM32x OBD-II interface and a GPS module, with connectors for the 1-wire and CAN interfaces, all in a package about the size of a tuner (longer and narrower).

This would cover everything I can think of attaching to the empeg, and still leave the sled serial port open for the things I haven't though of.