I have not seen anyone try to do this. Take a look at the Intel Galileo compatible shields list.
There is a Quad-band GPRS/GSM Shield listed.
Please provide more information about the mini-pcie cell modem and specs.
I have seen the Arduino compatible GPRS/GSM shields and I could probably make them work. However, I was looking for something that Linux would recognize as a standard network connection. My main application needs to run in Linux.
I have not selected any specific mini-pcie modem but I know they are readily available due to the fact they are used in many laptops and similar devices.
I have been using mPCIe card from Telit HE910, but with the Debian install found here: http://sourceforge.net/projects/galileodebian/ it will work as an PPP device (it will not recognize it as an ethernet device due the kernel version, needs newer kernel for that). The HE910 is available with an builtin SIM card reader which makes it easier to take it in use.