And no this isn't a spam throttle kind of request.
The idea is simple:
/whatever to open the window
It filters trade chat for the instances you look for based on keywords. For example ICC.*10|ICC.*25. It could optionally look for words like healer/dps/caster/mage etc to color the ones that look extra interesting.
It could be done in a lot of ways, I imagine a simple window that looks a lot like normal wow chat. Shows max 2-3 lines per person (as some people spam invites with macro's and use multiple lines), and resort instead of "reposting". So that whoever is still spamming ends up on the "new" part of the list.
Stupidly easy to do, I'd do it myself but I don't have the time. And it'd help a LOT. Hell it could even make a "standard" on how trade lfr requests look like, so that the addon could quickly recognize if you can fit in the group or not (aka this group has no caster slots/need only healers etc).