I don't think there will be. There is a Fritzbox, though, that does this job. If you look at kitz's forum, one member there has this kind of setup, though there is a lot of work involved to get it up and running.
The other thing to consider is that under Openreach's terms and conditions, the fibre unit constitutes something like master socket. Therefore it's untouchable by the customer, and if you fiddle with the unit, you can get fined.
I think it should be like on the continent that you can use your fibre modem, but I can't see that happening with Openreach or virgin media.
