In Germany, Kabel Deutschland has launched it´s own "Mobile Phone" sim card that effectively "kills" all previous tariffs for mobile voip if you have your own Asterisk server, or a Fritz Box 7270, 7170 etc.
With such a sim, you could phone your own box (if connected to a Kabel Deutschland landline) from anywhere in Germany and use call diversion, or callthrough for free! Well, for a monthly fee of 19.90 euro on the Paket Classic (6 Mbit/s broadband and 3 landline numbers).
Mobile voip is now dead, in Germany!
Kabel Deutschland mobile tariff
Kabel Deutschland Paket Classic