I think the Rodes are great mics, but for that kind of money I also think you would be better off to look at a different brand. The K2 has the advantage of selectable patterns, but the other specs on it are not as good as the NT1A. If you dont need variable patterns, then your NT1A is a better bet than the K2. Your KSM27 is no slouch either.
If you really need a different condenser with specs similar to the NT1A, I would look at AT or AKG. You will derive more benefit from having different brands in your arsenal rather than having several of one brand.
Depending on what you want to use it for, you might also look at a few of the better large diaphragm dynamic mics, like the RE20 or the MD421. You could get both of those for the cost of one K2. But you didn't say what you will be using it for.....