For the OP -
To add to a bit of Jester's explanation above, consider this.
The prop is like the transmission in a car. Compare this to a standard or manual transmission. The lower gears, first for instance, the car has a lower top speed, but it has "more power" and gets there much faster than in a higher gear, where a higher gear has "less power". So, you pick a prop that has a large diameter but a low pitch... say 10-4 which has a 10 inch diameter and a 4 inch pitch. The pitch is how far, in inches, in ideal conditions, the prop will move in one RPM. So, if it sustains a constant 10,000 RPM, it will move 10,000 inches per minute. You can do the math. It has more pulling power, in other words, than a 10-6 which would have more top end speed.
As for amperage or current draw, be careful and choose a speed controller that can handle the amperage that the motor will draw when turning to the max RPM. You could easily burn it out by "pushing" it to hard. Buy a watt meter - see the link.
http://www3.towerhobbies.com/cgi-bin...&I=LXLMV0&P=ML
This will give you the capability of measuring the amount of power the motor draws. Power = Watts. Watts = Voltage X Current.
You said "only brushed motors"? To bad because there are some real efficient brushless motors out there.
For batteries, look at L.I.F.E. battery packs.
http://www3.towerhobbies.com/cgi-bin...&I=LXYAS9&P=ML
There are several alternatives. Choose what will do the best work for you.
Good luck.
CGr.