I wanted to report tha Jack Orlando DOES run indeed with DOSBox 0.73 and without any tweaking with additional VESA drivers. This game is just a good exercise to understand how do the new supported graphic modes work. In order to get the game working i had to do the following...
1) I installed the game normaly with the default (in the config file) supervga_s3.After that i changed to vesa_oldvbe, and then the game worked fine!
2) If you edit the config file before the installation and change from the default svga_s3 machine to the oldvbe_vesa mode then the installprocess doesn't begin, because the program can't "find" the vesa support and aborts!
3)Finally if you install the game with the default svga_s3 mode and try to start a new game whithout changing to the oldvbe mode, then the game simply freezes!
Nice work guys! The new supported modes are valuable! And Jack Orlando is a nice game and a good DOSBox 0.73 "exercise" too! 😀