I get much feedback within the posts over the Lenovo Miix. I can imagine that other people have the same thoughts on the Lenovo like me. One thing i miss in the device is a 3G Modem. So i did again a little research over the connectors on my Lenovo.
There is on the lower side of the mainboard a M.2 or formerly NGFF port. There is no connector soldered at these pins in the non 3G versions of the tablet. The last samples which Lenovo gave to some authorities around the world for passing quality tests and regulations where shipped with an Huawei MU736 CF Module which is M.2 compatible.
Even if there is someone who get the M.2 port working for us there is still the problem that the simcard slot is without a frame for the card. Maybe there is something more missing on the mainboard.
I tried to figure out if there are pins on the mainboard where it is possible to connect a 3G usb stick but for more infos and a result I have to do little bit more research on this. For sure there is a USB port for charging and external connections. If there is a possibility to get a solution I am sure it will locate around the chipset of the USB connector on the mainboard.
There has been much success with finding additional usb ports on the Dell Venue Pro 8. Should apply to your mixes too.
Maybe someone more skilled than me can figure something out by comparing these boards.
http://forum.tabletpcreview.com/dell/60553-adding-128gb-flash-venue-8-pro-13.html