Welcome to the Indiana Thread housekat!
As far as building your coop on a concrete slab, the main consideration is drainage-- does a heavy rain flood the area, etc.
Welcome to the Indiana Thread stevekwan! Not sure about store locations-- you could Google. Check out craigslist for sale farm and garden, BYC classifieds, and perhaps there's a BYC Sussex Thread. Maybe some Indiana members from your area can help. I'm on my iPad, so I doubt the members list link shows up under my post, but you can use the link from jchny2000's recent post to see the Indiana members who live near you or those who have Sussex chickens.
CRSelvey, I have a galvanized hanging water thingy in our coop and I don't have problems with leaks/wet coop. It's fairly heavy with water in it, so it doesn't swing or spill. (I always have a bowl of water available outside of the coop when they're out for the day.
Animallover-- Great job! Congrats on your accomplishments. Can't wait to see more chick pix.