Ok, I'm sure this is an interesting question.
I would like to have extensions (in my house) for my cell #. So, basically like regular LL, but with old smartphones serving as extension phones.
Is this possible?
My notion is that I get a VoIP number that's the same as my cell number. Then, when I get a call, all the phones ring. I guess the only technical issue would be, if I answer on a remote phone, the cell tower should cut the call.
It would be even better if the system knows that I'm away from my house (and not ring the extension phones).