Thank you a lot! I also tried a search a bit and didnt find. Will try these (not sure if they will work on bigger resolutions, but I will give it a try

Edit:

It appeared to not working correctly on my Nextgen (probably resolution / version issue). After some research, I give a try 3rd party tool Blackr, it works reasonably well for AMOLED. It is manually controlled, whats quite an disadvantage, on the other hand, its universal solution for all other nav applications, which doesnt have screensaver option. Btw, as for my testing, only one of navigation I tested (iGO, Tomtom GO, Waze, TomtomAmigo, Sygic) has really reliable (I mean drives 70mins +) and working screensaver function within base package - Cruiser.