RE: RC Robot Speed Control Question
As far as that receiver goes I would recommend a different one such as [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXASY3&P=7]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXASY3&P=7[/link]. The one you have is for small airplanes and has a limited range of 620ft.
I couldn't find the exact motors you are talking about to find the specs but the speed controller would depend on the input voltage and the output voltage and i dont think those futabas would handle the 12/24v output. I would recommend these I have experience them and they can handle a lot [link=http://www.ifirobotics.com/speed-controller-selection-guide.shtml]http://www.ifirobotics.com/speed-controller-selection-guide.shtml[/link]
To answer your question about the speed controller supplying power for the receiver those futaba's do because they have BEC (Battery eliminating circuitry). Those victors I showed you do not have BEC but it would not be hard to just get a 4.8v receiver battery and plug it into the receiver.
I you could provide more information about the motors I could be more specific about what exactly you need.
Hope I helped
,John