When you configure a grid date-column with a custom format, the value configured in 'format' is parsed using JSON.parse. This requires the use of double quotes for both keys and values.

var a = "{0:dd/MMMM/yyyy}";    // example from docs
JSON.parse(a);    // SyntaxError: JSON.parse: expected property name or '}'

var b = '{"0":"dd-MM-yyyy"}';
JSON.parse(b);    // jey! 

However, if you use the latter, the generated template goes fubar with the message:

"Invalid template:' ... <td>${kendo.format("{"0":"dd-MM-yyyy"\}",theDataField)}</td> ... "

This makes sense when you look at the quote mismatch..

Grid should allow to place images in the header of each column instead of text on per column basis.

Add the ability to select grid rows by providing data objects from a viewmodel instead of specifying html/css selectors.

For example:

var myGrid = $('#myGrid').data('kendoGrid');
myViewModel.Items.forEach(function(item) { myGrid.select(item); });

I'd like to see an event for Grid contents modified (after-edit or after-add/delete, etc).  This would enable a sync with a DataSource, for instance, without further user action.  Presently, this is not easily achieved.

It's a common scenario to set custom css on <td> for specific column, for example, using columns: { field: "ScoreNumber", css: "right-align", title: "Score" } to get <td class='right-align'>, then I can make every every score field text-align: right.

Maybe adjusting _tmpl: in Grid Widget as 
rowTemplate += "<td" + (column.css ? " class='" + column.css + "'" : "") + ">"; is a easy way to accomplish it.

It would be nice to have the possiblity to toggle edit mode on and off for the Grid.
Use case: Often users find things that need changing whilst browsing data. In those cases it would be nice to have a toggle button in the toolbar that enables and disables edit mode. n quiting edit mode the users

include checkbox-based selection in the grid and allow the persisting of selections in paginated grid (i.e. user selects rows on page 1, switches to page 2, returns to page 1 --> previous selection is restored)

with grouping/sorting/fixed wrapper size + prevent default select

http://www.kendoui.com/forums/ui/grid/local-virtual-scrolling---my-changes-grouping-sorting-works.aspx

My changes: 
http://oskar.doppnet.com/kendo-grid/local.html
http://oskar.doppnet.com/kendo-grid/remote.html