It's a good question. I believe that if someone produced an original and professional classic game then many classic users' would buy it just for the novelty value of buy a 'new' game. I don't think you'd be able to charge very much for it though.
To sell the most copies you'd probably target a base 1200 machine.
i would buy a new game and i think it should be targeted at an expanded 1200 with an 030 etc and maybe take advantage of recent cool hardware like the indivision aga etc.
