I received an Excel alike prototype from Xinjie (xinjie.zhang[at]comforx.com) who's working for Comforx (China, http://www.comforx.com).
This app targets Flash and implements some basic formulas (SUM, AVG, etc).

Let’s try it by uploading your own Excel sheet, http://www.comforx.com/ExcelOnline/

Xinjie’s goal is to have a full featured Excel component using GOA WinForms for Flash. Comforx should release this one, integrated into a full packaged web 2.0 application for a customer being an electric plant in China.