I have no idea on whether it's actually possible... but I doubt it. This was originally a limitiation in an old version of Excel, I think it was Excel 5.0/95. So more rows than that is actually stored internally in the file in an incompatible way. Just like the old limitation of cells to 255 characters, you occasionally get weird results if you have longer text in one cell, simply because there are several ways to store the same data in the spreadsheet.

I guess that if it was simply possible to get past the 16383 rows limitation in Spreadsheet::ParseExcel, that it then would support it transparently, without any action required from your behalf. And that's why I'm guessing that it is not possible. Not with the version of the module you have. Perhaps in the future...

But actually, it's just a guess.