Thanks to all of you for the warm welcomes and recommendations.
I will pursue a couple of the proposed avenues and read in more on mame. Hopefully I will also be able to contribute somehow with my rather deep insights into Computer Space, Monaco GP and others. At least Computer Space is very well documented as VHDL code at KLOV/VASP - http://forums.arcade-museum.com/ for anyone who is interested - and also readily downloadable and playable on altera de0 dev board.