Thanks for the April reference. In the post [1] there are just 11 comments and also it seems that the intended audience could maybe two dozen people!, not very encouraging to create a J in Common Lisp.
I'd be a very interested admirer, if not user, of such a project. I'm playing with J this past week, and otherwise have a couple of CL books under my belt. No other real experience programming, but I certainly think that sounds like a cool idea.
I wonder where April would fit in, with your idea? Joining forces with the fellow who made April might be a possibility. Strength in numbers, and all that.
[1] https://news.ycombinator.com/item?id=22225136