I saw this stuff in one of the newer Popular Science issues. It seems pretty cool; the tube is lit by an LED at one or both ends. The bulk kits are mainly what they sell in the store, but you get ALOT of tubing. 180ft for ~300$. They also sell demo kits which are 21inch pieces for $29. I dunno how this compares to the price of most neons, but it can't hurt to have more options.
http://www.luxaura.com