sorry calum but im going to completely disagree with you :P.

I have used the planet T5 and the spektrum dx5 and i prfer the palnet t 5 , regardless of price. The dx5 feels cheap , its too light and just dosent have a nice feel , also the binding method is rather questionable. The planet T5 though feels a lot nicer , it is nicer to hold and use. This is purely subjective, but as for the interferance problems people have created about the planet T5 , well im gona say thats rubbish until any set produces any type of interferance ( hasnt happened yet).

As for motors , ifyou are definitely sure you want this bot to carry children (lol), then scooter motors would be your best bet. They are simialr to drill motors in that they come pretty much pre assembled witjh all the gearing done for you , but they have more power. If your after true power then a pair of gold motors would be good , but you will probably need quite a bit of help on the gearing.

As weight seem unimporant in tyour application id use the sla batteries that come with your scotters or the nicads that come with your drills. Youll get an acceptable run time and you get a charger to.

As for the esc's , if you have a veyr big budget and you dotn require that mcuh fine cotnrol then , (this pains me to say) get 2 electronize esc's. If your budget is smaller and you decide to go with drill motors then a sabertooth 10 A will be fine. If you end up using scooter motors or gold motors then a 15 A electronize is going to be right on the limit ( they relays in them are only rated to 10 A anyway !!!!!) . You coudl always use a switch or relay based system for any of these motors if money is tight.

EDIT: As for the wheel chair motors , they might be a little over kill and any bot you decide to make out of awheel chair is going to have to be a heavy weight , and tbh , no offence but its a bad idea to build a hevay weight as a first robot.