As I see you have posted a support ticket for the same issue and we have replied to you in that thread could we continue the discussion there?
I will post our response from that thread here too in order for it to be available for the community:
In the current version of RadGanttView control it is not possible to achieve the described behavior for the rows. The reason for this is that currently you cannot pass enough information from the tasks in the rows to the rows themselves in order to customize them based on a specific task.
We will research the possible solutions to this scenario and we will do our best to implement it as a built-in feature for our future releases of RadControls.
the Telerik team