http://www.nano-reef.com/forums/index.php
Shows how people set up their nanos including the best filters, fish compatibility lists, lighting reviews, etc. Has excellent step-by-step how-tos. Even shows how to modify the cookie-cutter systems to optimize them.
Saltwater tanks in general are a lot of work. Nanos, believe it or not, are even more. Because the water volume is so low, changes in water parameters can happen very quickly with deadly consequences.
People go well past the 10 gallon limit to much smaller set-ups, but even a ten gallon tank is difficult to maintain. It takes vigilance with regards to maintaining water quality, stabilizing temperatures and making sure stocking lists are compatible.
Even with a ten gallon, you would want to go to an external sump to increase the volume of water in the system. Depending on what type of corals you choose will determine lighting. The lighting type will determine if you need a chiller, and so on and so on.
I used to keep saltwater fish and had two nano set ups. Currently I have over 30 reptiles and can tell you that maintaining those two nanos was more work than caring for all of my herps.