After hours spent on various forums (including this one of course) i decided to go for Sierra Wireless MC8775 card as significantly faster than original MC8755. I asked for modified Zander BIOS, but unfortunately Zander not been here for a while, so i had to search for another BIOS.
I found on ebay cheap sim card socket and good price for WWAN antenna together with LED sticker. Finally ordered HP version of MC8775 card (HS-2300). Pin-20 solution was required as my modified BIOS is not as good as Zander one, but everything is working just fine.
After firmware upgrade i'm getting quite good transfers:

Cost in total - less than 40 pounds.
Next step is 802.11n wireless card, waiting for Intel 5100agn card just ordered on ebay.
So - if you dreaming of 3G connectivity without any bulky 3G stick trying to rip out yout USB port - don't hesitate, upgrade your precious Thinkpad.
EDIT: now upgraded to Wifi 802.11n with Intel 5100agn






