Well... you could make use of the new application management uri features introduced with firmware 8.3.5 (check the ccm7 ip phone services developer guide for details) and for instance use the onFocusLost uri to notify the application that it lost focus - you could then push a notify uri to the phone that brings the application back into focus. The syntax to be used is

App:RequestFocus:0::" + pc.serviceId

where pc.ServiceId is the application identifier of the your application (those identifiers are another new concept introduced in the 8.3.5 firmware).

I'm using this approach in one of my own applications and it works quite well (though I do the whole thing jtapi controlled... so I don't need the notification that the app has lost focus but I know when a call comes in I'm losing focus and have to push the application back to the foreground).