Yes, we can't be hacking our current Snap! version.. But we can share "special day" projects (on Snap! web), as challenges, with ideas like this one. The first, "Chursch's day challenge", hiding blocks and with a challenge written inside.
Nobody seems to agree with me about this, but I would not introduce recursion with an example that could be done by looping. (Well, except by implementing a stack and looping through a stack-based interpreter.) The way to sell students on recursion is to start with a branched recursion -- two recursive calls in the middle of this call. Like vee!
Do you mean the branched tree? I like to introduce students to new computational tools by using real world (non-abstract) examples. So, for example, they could use recursion to work on files in folders inside folders, etc. Do you have better real world examples (i.e., no mathematics, no fractals, etc) for using recursion?