USB to dual serial interface board (RS-232, "sniffing," etc)

Is there a board out there that has one of the standard USB to serial converter chips on it… but with two serial ports rather than one? E.g., the FTDI FT2232? I’ve been thinking this could be quite useful in the following form: A small board with a mini-USB connector on it and then 2 10-pin (or so) .1"-spaced headers, one for each serial port. You’d then plug on a daughter card provide various different bits of functionality to the board:

– A pair of DB-9 connectors (i.e., the daughter board would just add Max232-like level shifters). Alternatively, mechanically things could be arranged to allow two daughter boards, as arguably one might want, e.g., a true RS-232 port along with a logic-level serial port.

– A “sniffer” board, where you still have two DB-9 connectors, but they’re intended to go in-line of a regular serial connection and both Tx and Rx of that connection are “sniffed” and sent to Rx 1/Rx 2 of the main board. (And presumably Tx 1/Tx 2 are logically “added” to the regular connection as well.) ← This use is what really made me think of this; I’m doing some serial sniffing right now, and while it works fine to use two USB to serial adapters, it’s definitely a bit messy with all the cables and needing two USB ports and all.)

– Custom serial interfaces for, e.g., cell phones, radios/media receivers, etc. (E.g., for Sirius satellite radios, there’s an 8-pin mini-DIN connector that’s just serial Tx/Rx at 5V logic levels, power, and left/right analog audio… you’d break out the power and audio and route Tx/Rx back to the main board.)

Anyone else have any interest in this? If a handful of people are interested, I can make some of these myself and sell the ones I don’t need (…although we’re probably talking ~$40 boards here, given that I’d make all of 10-25 or so).

Thanks,

—Joel Koltner