Gradient Red to yellow/orange etc wigs?

I don't know any specific wig makers because the one I know is closed, but a good place to look is to commission a wig from the marketplace.
The ones I've seen is the base wig is a fur wig with synthetic extensions sewn in the bottom.
I'm not sure where to go if you want a full synthetic wig, but you've got the right idea about how to make it, although I think sewing the wefts in might be easier because it might get messy with the glue going everywhere and it may take a while for it to dry depending on what you use.

 

http://www.jpopdolls.net does a lot of two toned wigs, i found one that was blonde on top and the orange at the bottom but I guess it should have been the opposite.
I'm also a bit confused..
First you say red to yellow/orange
Then show blonde and kind of cherry red hair but then also mention carrot. ^^;