Hi Mark,
Please refer to the below forum thread that demonstrates how to customize the drop down GridListControl.
http://www.syncfusion.com/Support/Forums/message.aspx?MessageID=19403
The DropDownGrid cell type can be tried and there you can have a GridDataBoundGrid as drop down grid to use the GridBoundColumns. Refer to the sample in Syncfusion\Essential Studio\4.1.0.62\windows\Grid.Windows\Samples\In Depth\DropdownGrid\ to know more on DropDownGrid cell type.
Let us know if you need any further assistance.
Regards,
Calvin.