Othe tanks you can get are the oceanic biocube, or the jbj nanocube. Some other cool tanks are the
http://www.redseamax.com ,
CADLIGHTS tanks , or my favorite,
Solana - Aquarium System | Current What's Next
These systems range for $250-$800 depending on how big and what type of lighting you want. If you do with the kit tanks I would suggest gutting the filter and upgrading the skimmer. Filters only collect detritus and give it a place to rot and create nitrate if they are not constantly changed. Running your system without them makes it even more resistant to problems. There are after market skimmers that you can use on these systems that will greatly increase the ease of keeping the system.