1. Select all button 2. Remember selected items (now they are gone if we change page / scroll in virtual scrolling mode on) 3. Selected items count displayed on bottom bar (for example put it as neighbor of paging list) 4. Copy content of selected rows in grid (ctrl+c when selected) [data split with semicolons] 5. Export Selected/Filtered data into CVS file
The behavior you describe is pretty much covered in the spreadsheet component http://demos.telerik.com/kendo-ui/spreadsheet/index