Far from identical, but along similar lines: http://treesheets.com/

"It's like a spreadsheet, immediately familiar, but much more suitable for complex data because it's hierarchical. It's like a mind mapper, but more organized and compact. It's like an outliner, but in more than one dimension. It's like a text editor, but with structure. "

You can nest spreadsheet-like cells within cells within cells within cells.. and zoom in and out between the various levels of nesting.

For Windows and Ubuntu, with a beta for Mac OS X available.