When did you purchase your x61? I was actually surprised that when I opened up my system it had the fan installed. But yes, if you didn't order the WWAN you do have another slot open.

You have 2 slots. I have my Atheros card from Lenovo and then installed the ITM that I received later into the second pci-e slot.

Pretty sure you're going to have to use an external DVD-drive.

On this regard are you talking about with the AC adapter in or on battery?

On AC it gets pretty warm but not to hot.
On battery the thing barely gets warm.