Thanks for writing this, it's adjusted my thoughts on invocations somewhat, and seems a great guide.

Anyhow, I'd like to point out the Ghostly Arms graft from Libris Mortis. It doesn't replace arms, and gives you ghost arms, 1 per 6000gp (3000 if you craft them), double for a set of hands, and this gives you an extra invocation if you have multitasking (Also, you're the only other person I know who actually noticed this for their guide, so grats!). The net effect is that you just dismantle the action economy 12000gp at a time... Too bad you can't use Flee the Scene to move and shoot due to it being a dimension door effect.

Also something I'm not sure you noticed, with some invocations being CL based it's worth taking a look at Elder Giant Magic if you go the giant route. Up to +3 CL, albeit at the cost of 3 relatively easy concentration checks (At the level it's available) and 3 full round actions. So if you can set up an ambush or something big with a CL effect, go nuts. But probably better in games where you can get homebrew to actually access more cl based invocations.