These are just some micro hobby servos (Hexatronic HXT 900) I'm hooking up. If I hook one up to a power supply (which there is no problem powering) and measure the current whilst holding the servo arm in place with my hand to simulate a very high load, it seems to use 750mA. Letting it run free, it was around 75-125mA depending on the speed I set it to move.
So with that, in theory 4.5A is needed if all servos are under very heavy loads and I also need the 4.8v-6v of power for them in general. It is extremely unlikely that all servos will be under such heavy loads, I would imagine at most 2 servos would be, but for very short periods of time (10 seconds or so), but I want to make sure I cater for this situation.
Is it possible to even draw this much current from 5 or 6 AA batetries whilst drawing 6V, as it does sound like a huge amount?
One thought is that the voltage regulator says it can only deliver 1A. Is that the problem? Would I need a regulator for every 2 servos so each can get at least 500mA (so for 6 servos I need three regulators)?
I gave a 9v battery a try and it only managed to power 3 out of the 4 servos when it connected to the circuit (so 2 voltage regulators are in the circuit I tested. One 5v regulator for the atmega328 chip, and one 6v regulator for the servos). However, I checked the 9v battery voltage with the multimeter and it only measured 8v, so the battery probably hasn't got enough life left in it.
The project is going to basically be similar to one of those robot arms, and I need 6 servos for all the various movement areas. As it's stationary, a wall pack is certainly an option, but I did want to see if batteries were viable as that would be the more preferred option, as I'm not sure if it will be near a wall socket.
If someone knows of a DIY tutorial for robot arms like this I probably would be able to learn from that also. The only problem I have is they all seem to use kits or hack store bought robotic arms instead of making you build one yourself completely from scratch with the electronic theory work. So they're all pretty much saying "just plug this into this", without an explaination of how the circuitry works or why you're making your circuit in that way 
Again, really appreciate your feedback. One day I will understand all of this!