I don't know if it is what you are envisioning, but there is a spreadsheet program called Scheme In A Grid (Siag) [1] (part of Siag Office [2]).

From the "Introduction" [3] of its Online Documentation: "Siag is an X-based spreadsheet for Unix. It uses Scheme (a Lisp dialect) both for expressions and as an extension language, which makes it easy to create new functions (for native Lispers, that is). There is no requirement to know Scheme to use Siag, expressions can be entered in traditional spreadsheet syntax as well."

[1] http://siag.nu/siag/

[2] http://siag.nu/index.shtml

[3] http://siag.nu/online-docs/siag/intro.html

That's about what I imagined.

This is fine and dandy for small sheets, but if you're trying to build a sheet with multiple tabs, circularity, self-referencing IF statements, or lots of data, it will get really hard

Also, the #1 Excel rule in Wall Street is "never use your mouse"

IMHO, I think the better project is an equivalent of an RMarkdown / RStudio tool that generates a final report from a declarative set of instructions.

This exists already - Jupyter + Python + Pandas.

Or a spark interactive cluster with a notebook interface if you have more data than can fit on a single machine