This is not very helpful to the OP as all he/she wants to know is if the carrier in the iphone 5 will short the contacts at the edges of the "nano SIM".
It is my educated guess that the material the SIM carrier is made of is the same as the iphone 4S albeit that it now carries a NANO not a MICRO SIM.
It will therefore be insulated as that would make sense given the very close proximity of the NANO SIM's contacts at all edges.
The thickness may be an issue, but SIM cutters have been available for the NANO size for a while and all the information seems to be that once sanded down a little (less than 1/10th of 1mm) the SIM is of an identical spec electrically as carriers for NANO SIM to convert to MICRO and full size SIM are already available.
This is so that if you wanted to move your SIM (either permanently or temporarily) to say an Android phone (as I often do because the data allowances etc are different on the 2 contracts I have for our phones) you will be able to do so. I note the NANO SIM carrier/convertor is plastic and insulated, gives a clue as to the iphone 5's SIM carrier status.
Still no promise from Orange (UK) to provide NANO SIMs for Apple purchased iphone 5's. I note that not many "official partners" have the 64GB model. Therefore if you want the 64GB model on Orange/T-Mobile then you have no option but buy from Apple and then ask for a SIM from Orange.
However, they are saying elsewhere that if you go to an Apple Store on Friday they will have plenty of NANO SIMs for the '5 that can easily be activated within 24 hours on your chosen carrier.
In the UK Three (3) will send you a NANO SIM "within 5 working days" and as they do 1 month contracts that may be an option for those UK customers of Orange/T-Moobile who feel badly let down by the whole experience (Apple Partners or not they screwed up badly with this).
It does not help to know that Vodafone UK has 500,000 of the NANO SIMs stockpiled!
Should Apple have not made sure that their "partners in crime" were well stocked with SIMs and an active upgrade option in place BEFORE selling the '5 to an unsuspecting public? After all, would a non techy purchaser be expected to know the new device has a new spec SIM fitted? No, probably not. So doubly important that the customer experience be smooth and without glitch.
Apple CS at their stores is supposed to be legend, so I expect that is were they willl be doing the CS work for several major networks that were either too lazy or too stupid to do it themselves on Friday!