yeah prolly you could do that,but you could prolly go to your lhs and ask if they can get a motor,preferably a novak system then they might be able to tell you i am doin this to my old nikko but its kinda gunna be a little smaller and slower than you are wanting.if you just wanted to you could actually build your own chassis and put some kind of electric motor in it with a good setup of suspension in it.
heres a pic of my 1/4 scale rock crawler i have been workin on ino its not electric but it is one that i am building and it has been a cheap build so far.its really light too.but this is to give you some inspiration to do what you want to do.
and i built a dirt tracker that i havent finished and i sold it but now i have bought it back b/c i have missed it and i want to continue on it as much as possible.it would be cheaper in the long run if you were to convert a toy grade rc into a hobby grade but you can make up your own sleek lookin car that you really like that will be a one of a kind and probly be alot faster if you got your hands on a high volt motor