Interesting question. Haven't seen anything that can be used for this. The PCMCIA port extenders or port replicators i have seen are usually for laptops or desktops and not sure they can be used for the MB6000.
No the MB6000 is not slated for a USB port upgrade. The MB6800 has the USB port and we do have PCMCIA to USB adapters. On the other hand the
PCMCIA to USB adapter is not cheap either (~$169). Also note that each time you do a port conversion you inadvertently throttle your performance albeit by a small amount so unless the mounting convenience is absolutely critical for the price of adapters you would be better off to purchase a router with the right form factor to suite your mounting location.
Incidentally as an aside if you're data card inside the MB6000 is obstructed you may be loosing performance due to a low received signal strength caused by RF-shielding. This is a simple problem to fix though using cellular booster antenna that can move the radiating antenna away from obstructions. For example
this.
