You will be able to connect a second Slingbox at home, it will work very good, of course that it will depend on the Internet speed at home so you can get a good quality. Example; If you are connected remotely to one Slingbox using your computer and also connect to the 2nd Slingbox using your Droid, probably the picture in both devices is not going to be the best quality you will get since you only have 1Mbps of upload locally.
For the configuration of the 2nd Slingbox you can use a different port like the 5002 or 5003, that's not a problem, you just need to run manually the setup of the Internet Viewing. You can use the Network assistant to do that;
Let us know how it works.