Help with creating a "spreadsheet"

[berger@SOE.Berkeley.Edu (Daniel Berger)]

I am about to create an application (an intelligent tutoring system) using
MCL that will need a "spreadsheet" as a tool.  Has anyone out there created
a "Spreadsheet" - or a table with individual "active" cells, selectable
rows/columns?  I am not too concerned about the internal issues
(i.e. computation, calculation between rows & columns, ...).  I am more
interested in ideas on how to create and manage the window.  It may be
possible to start with the table/sequence dialogue type (this would be
nice because I would not have to worry about scrolling, redisplay, etc...),
but adding columns and rows may be cumbersome with this MCL dialoge type. 
So I am leaning towards creating the whole thing from scratch.

Suggestions?  Ideas?

Thanks
Daniel

berger@dewey.soe.berkeley.edu
510-643-8858