edit: changed something that's bugged me for a while, uploaded larger resolution!
I vectored this out for a holiday gift for a friend, but you can have the background and use it for whatever you will.
Time to make: about 1.5 hours of actual work (but 3 days due to my laziness and sleeping)
Gradient Note: I tried to use as many gradients as I could to really capture the cloud coloration.
Program used was Ponyscape.
's modified Inkscape so you'll need that if you want to use the SVG files with all the AWESOME options.
For the latest version, visit his journals! [link]Ponyscape is the easier-to-use, great for any skill level free vector program!
Even better, the symbol below means you can use it as long as you attribute me and don't use it for commercial purposes!
Background traced from screenshot of S1E16 "Sonic Rainboom" of My Little Pony: Friendship is Magic which is copyright Hasbro.