Peter, I have one and like it, but it is very large and heavy. If I was going to travel much, I wouldn't choose the 9300 -- too big and heavy.
For my purposes it is perfect and I like it a lot.
new dimension 9100 & ide hd backup
I have not a real answer for your question but maybe I have a worthful hint. I've been...
I'm not positive of your answers, but I believe the answers are 1) External (from a google search as Dell.com isn't clear), 2) All three and 3) No
The DVD drive is held in with a screw, which leads me to believe that it isn't easily swappable. Not hard, but not intended for a battery swap.
My approach to TV on my I9300 is to use an older desktop as my media server. I have three Hauppauge TV tuners and use Snapstream's BeyondTV to record TV and automatically convert it to wmv files. Those I copy to the I9300 and watch in Media Center.
Media Center really requires wmv to play videos properly with the front will.