Indeed combining all of the scripts up front can be a great strategy. We have some ideas on how to make this easier in the future versions, but for the moment this has to be done manually. We have a tool that can list all of the loaded scripts on the page in the correct order.
Open the attached web site and place all the controls that you intent to use in the ScriptResourceDetector.aspx page. Run it and you'll get a list of the ScriptReferences that you need to include in your RadScriptManager.
Keep in mind that upgrades to later versions will require an update to the scripts as well.
I hope this helps.
the Telerik team