I'm still curious as to why you would need more than two levels of var expansions so often to make it a generic omnipotent bang.
i.e. from your other post:
You plan to have variables for all the possible combinations, per tmp ? And then the same for other things? I'd like to dismiss it as a bad choice in design, but maybe you're on to something powerful here.

I'm just saying this all seems like it's geared to work for the "proper parameters" you present. I think you would need to use a stack to be able to expand all possible formats of nested variables. I don't know if you would want to pursue making that in current scripting while waiting for better days, those without multiple escape code paralysis.

Here's something untested of lesser ideal anyhow:
Then on a case-by-case basis you could do things like this:
Sometimes I think I abuse varnames :S