I think what you're looking for is kind of a special case.

This TP is my first smartphone, or anything running windows mobile, so I can't really speak about any programs that I've seen in the past, sorry I am sure, like you say, someone has made a full screen caller ID app, but I'm unaware of it.

Try this in your S2U2 settings:

In the phone section...
Set Caller ID to "Full Screen"
Set Slide to Answer to Off

I don't have another phone around to call myself with, but what does it do when you have it set that way? You may have to pick up the call using the phone's hardware keys though.

Edit: Also, your car looks great