Using a regulator would work as far as lowering the voltage, but I can't think of any reason to use one, as opposed to just lowering the number cells. A linear regulator like the one in the link has horrible efficiency- The power it dissipates is equal to the voltage drop times the current. I.e., power and flight times would be the same (actually better due to the lower weight) for a system with fewer cells versus more cells and a linear regulator. A switching buck regulator would have much higher efficiency, but if you want one with high current capacity, it's expensive and could be heavy due to the large inductor. Also there is a RF interference to worry about from the high frequency (ranges from 100kHz up to 1MHz or more) and high current (radiates more RF energy.) Better to not use one and lower the number of cells, add weight by using cells with more capacity for increased current and/or flight times.

www.cheapbatterypacks.com has a extensive list of cells of all sizes and types. Although their max current suggestions are a little optimistic IMHO, you can get a good idea of what is out there for your app. Note that the really high capacity AA cells are NOT suitable for e-flight, they are are for transmitters and glow plane reciever packs.
Andy