The actual Tx module of your Eclipse 7 is just there to convey the positions of your gimbals/switches/sliders to your receiver. In this case we're talking transmission of those endoded signals via radio, but you can transmit those same signals via any medium you so desire - whether it be infra-red, or light, sound, whatever.
So I'm taking a gamble that your Tx could well indeed be converted to work on 2.4GHz. That would be the easy part. The hard part would probably be trying to stuff the the 2.4 Tx module inside your Eclipse without recourse to some major surgery, thereby invalidating any remaining warranty. But so what?... warranties are for wimps, right?
Maybe one word of warning, though....
Some 2.4GHx Tx modules will not transmit more channels than they're designed for. For instance, a 7-channel Tx module will happily work alongside any 2-channel / 3-channel / 4-channel / 5-channel / 6-channel and 7-channel radio, but it will not recognise more than seven. If you try to stuff more than 7-channels up a 7-channel Tx module it means you lose those subsequent channels.
Regarding Futaba Tx modules, for instance, as far as I'm aware theirs only go to 8 channels max. (but don't quote me on that). Futaba sell Tx's with a maximum of 14 channels these days, but I believe the actual Tx strip is integral to the radio itself. i.e: you cannot purchase a separate 14-channel module.
Good luck.