spurperl,
The limit is per sheet is it not, with the number of sheets limited only by available memory? I assume you can create a graph that uses data points from multiple sheets. I have only used the Spreadsheet:: modules when playing with Excel otherwise I would try to put something together for you.
The limit is indeed per sheet... but you're right, it might be possible to combine from multiple sheets, though I fear I may run into the same limitation with charts.
Anyway I'll give it a try, thanks.