What if you use the passthrough that came with the TP2? It's got the power in the bottom, and in the side it has 3.5, 2.5 and USB jacks. One could plug the ebay FM on the USB jack.
I see dead phones, calling around just like regular phones.
My cell phone history: Ericsson GH788, Mitsubishi T200, Sanyo BAM 201, LG V111, Ericsson T28, T39, T68, T68i, Panasonic GD87, GD55, Nokia 3660, 6600, Motorola V525, A360, Panasonic X701, Palm Treo 600, HTC Blue Angel, Wizard, Herald, Kaiser, Touch Pro 2, Doubleshot MT4GS