Right now, no player is allowed to carry more than one ID in his cargo hold.
My suggestion is to ammend the Smuggler ID to include "Smuggler ID allows it's owner to carry additional un-mounted ID's in it's cargo hold"
Yes, it's illegal, but that's the point - any smuggler caught with more than one ID would be punishable in-RP by the local law enforcement (carrying 'fake' ID's, basically) - but this would allow a smuggler to 'set up' someone else with a new ID for a fee, lending more to the black market RP for sirius.
So basically, say someone wants to get into the ranks of a certain faction without actually being a member of that faction, they could contact a smuggler who could forge false identification papers (an ID) and sell the to the person in question. Of course, the person who gets the new ID must still follow proper equipment and ship rules for the faction ID he's now using.