I already did:  http://bitcointalk.org/index.php?topic=506.0

I've given this issue more than a little thought, and it is something that could have some more effort put into it.  A related concept is how you can keep "sub-nets" of some sort synched with each other if they weren't directly linked to the main internet with a presumption of ping times less than 1 second.  This could include 3rd world countries where Bitcoins could be shared on a thumb drive and shared by SneakerNet or between LANs that might have their external connections severed due to natural/man-made disasters (including war or civil unrest like what happened this month in Egypt).

Making the Bitcoin protocol a bit more robust to deal with this issue could be useful, particularly if it is going to be used as a cash-like currency.