I don't think this is what you're looking for, but have you tried convincing non-R users to use the new RMarkdown visual editor?
I realize that some people may just never be R users, plain and simple, and there needs to be a solution for that. But I've found that if I can get people convinced that all they need to do is install RStudio and open one document I've sent them, they tend to be open to it. And since the visual editor doesn't look like code (it looks more like a word document!), it can be a lot less intimidating.
That said, I'll be curious to hear how/whether others have dealt with this when collaborating with people who just don't or won't use R at all.