I know it's the opposite, but I have been using my Verizon Galaxy Nexus 4G LTE (rooted of course) to use it as a hotspot so my iPad mini is basically a WiFi+ Cellular.
Vz fully supports the Mini + cell data as a wifi hotspot and BT tethering and it works just fine. 'm not sure how many can connect at once but I have tethered 4 devices simultaneously.
The Hotspot function is part of the data plan. With AT&T you have to have the $50 data plan for the Hotspot function which is why Verizon is better in that regard. Verizon has Data plans that start at $20 for 1gb I believe.
It works as an ad-hoc connection and requires a password, but works well. I streamed shows maybe 30 minutes at a time without a hiccup on a connected device (an Ipad 4). It never dropped the connection or had any issue at all, I was very impressed.