I have altered the kendo code to add row and column references to the k-spreadsheet-cell dom objects. A sample of this is: 
<div style="color: rgb(81, . . .  class="k-spreadsheet-cell r17c1 row-17 col-1"> . . . .
I have items that I wish to place on top of cells in the spreadsheet.
I can use these classes to identify the dom element corresponding to a spreadsheet cell object. I wish that this thing would let me post images. This is working really well. 
Request: It would be nice if the spreadsheet code to do this out of the box. Further, it would be beneficial to add a 'tag' property to a spreadsheet cell that would be indicated in the cell's dom object. If a cell has a tag, it should be rendered even if it doesn't have non-trivial formatting or a value.