Are there any spreadsheet widgets for Android?

Why not use a TableLayout widget and programatically fill in the rows and columns while looping through the excel data? TableLayout supports rows and columns.

Usage example: http://developer.android.com/resources/tutorials/views/hello-tablelayout.html

The best next thing to writing your own from the ground up:

If android-spreadsheet hasn't helped enough,

the work done with Calligra on Android is the furthest along.

or waiting to see if the LibreOffice Android port will be of any help.

Calligra will at least be some assistance to the problem.

I'd also add, the suggestion @Vincent offered in the comments isn't too terrible. Most phones/tablets come with a stock Office Suite for viewing (not editing) purposes. I understandably see the pitfalls in that solution though, but it would be much easier, albeit lazier.