What do you think of the inflationary universe? It works out to a total universe as much bigger than the Hubble volume as earth is to a grain of sand. One good thing about that model is that it explains why the universe appears so flat, isotropic, homegeneous if we can see only a tiny piece of the whole, which would be curved back on itself.
I found it 'upsetting' at first, until I learned to understand it a little better. (I'm not an expert at this stuff - Radio Astronomer is probably a better bet - I've had one grad level course in G.R. and a lot of particle physics, but that's about it.)
Apparently, in the inflationary model, there can be regions located outside our own observable 'bubble' as a result of the inflationary epoch, traveling away from us at (an apparent) 'faster' than light, but since we are forever causally disconnected from those regions, it doesn't really matter. Relativity's limit still holds from any observable point.
(One day, I'll understand this better myself, I hope.)