Thus the 319 is take off performance limited and fuel tankage has nothing to do with it.
As I've said before, the weight restrictions do come into play sometimes. The A319s are certified at various MTOWs throughout the fleet - 62, 64, 66 or 68 tonnes. I remember operating a flight from the south of Europe where we had to offload about 6 passengers + luggage because we had a 64 tonne aircraft and an 80kt headwind component all the way back. If we'd had a 66 tonner, we'd have managed to carry the extra fuel and would have been OK.
The restriction was due to fuel capacity with the already high payload, it was nothing to do with performance restrictions, 22k or 27k engines or anything of that nature.