There seems to be flooding issues with the newer locking tanks like the AGR and Artemis tanks. Since they are in their first versions I might hold off on purchasing one of them. I've personally never seen the need for locking tanks, as all of my tanks have never been "slidey" in my year of using cartotanks pretty much exclusively.
Flooding for the most part has more to do with the cartomizer than the tank, and more often than not with user error.
I happen to prefer the IBTanked pyrex tanks ($25). High quality and affordable, the 19mm is the same diameter as the Provari's top cone. Sometime in the next month they will be coming out with a 22mm width that will be the same diameter as the Provari body and Hippo attachment.

http://www.ibtanked.com/
Phiniac is generally considered to be the most durable pyrex tank. It will be significantly more expensive (start at $38), but you can customize it with colored glass, sand-blasted designs, textured glass, or 3D glass-blown designs should you desire to. It will be a little wider in diameter to a Provari. They come with delrin endcaps, and sometimes have stainless steel caps for additional money.

http://phiniac.com/
Vaporfexion makes a Pro-V tank specifically to look good on a Provari. May have limited availability, and will be in the upper ranges of price. ($58 and $80).
http://www.vaperfexion.com/the-pro-v2/
http://www.vaperfexion.com/cartomator-pro-v/
I have other tanks that can be viewed in my photogallery:
http://www.e-cigarette-forum.com/forum/members/baditude-albums-pictures-my-setup.html