Sorry for the late reply, I just saw this. Let me give a more thorough explanation here but I do agree with
@Divine's comments.
Now a .gif sure yes it has this animation effect you want, but it is also not an ideal format at all when it comes to quality. This is because it can only store 256 colors maximum. If you have gradients, hues, shadows, highlights, the whole thing then all this become very very blurry and distorted. I do get why you would want to have such .gif as your desktop image, however I personally object to it and therefore no I do not take up the ''challenge''. I'd like to explaining my reasoning a bit better though if you do let me, here's why:
1. A professional would never accept their work to be displayed or even saved as a .gif, precisely for the quality loss and for it being pointless. If you want something in top quality (or even if you don't), but from the moment you're asking a professional you can't expect them to lower their standards.
2. I do not find this a ''challenge'' at all because there's absolutely no difficulty in making a .gif image for desktop and well mind you if I am to make something for somebody I make them all in print versions and therefore over 7000px, too big to become animated.
3. Look for quality, always. A .gif won't give you that, and those who claim to be able to do it then always expect a
flaw in techniques, or
flaws.
4. If you want something animated then its best you go with a short clip version, aka movie, just for the sake of preserving the quality and colors.
This is all I can think of for now. I have no issues being commissioned work but when it doesn't fit my standards I suggest other options or reject it so I'm sorry for that -- always happy to make you something in high quality, crisp and clear though
cheers