What do most Dell laptops have a SIM card slot?
This morning I found a similar in my Inspiron 1525, and I was very surprised. It is located under the battery, just like in the phones.
In the picture there is a connector for the Vostro 1400, as there was no camera at hand.

As it turned out, this connector is designed for use with optional built-in gprs / hspda-modems, which I did not have. Very prosaic, but for me personally this engineering solution turned out to be an interesting discovery.
Hope you enjoyed it too :)