Are you familiar with Carto tanks?
Also note that those are 'grommet' tanks, and while i personally dont use carto-tanks, i have seen several of the veteran CT users (such as Baditude, go read his blogs on the subject) mention that they don't care for grommet style tanks anymore.
If you understand the in/outs of carto-tanks and how they work, have you considered an IBTanked or similar mid-range non grommet tank?