We'd need support for checkboxes columns in the new Spreadsheet control.
Checkboxes could be implemented as part of Form controls support in the Spreadsheet. Here is some further info on how they could be used in Excel:
Allow us to add a checkbox for Spreadsheet.
This sounds like a good enhancement - ideally one should be able to provide custom cell renderer in HTML. Its available on the other Kendo products, just not the spreadsheet control...