Here's just a suggestion .. make a small sample at a reasonable price that is at little cost to make and see how it goes. If it goes good, then great, if not..we'll hey there was little risk to begin with. Maybe even bundle it with a well tested battery so folks don't have to go all over the place to find it.. Folks need the battery solution before the cover am I right?
Or .. if you really don't want to get into any of that you can always post a step by step guide in Spanish or with lots of pictures and if we want it bad enough we'll find a way to translate it and make it happen.
Me? I just so happen to not be into building stuff and would rather pay if its reasonable price and a good solution.