Highest proven MAME score is 41,260 by Franklin Cruz.(posted 8697 days ago)Highest score at Funspot was 48,480 by Perry Rodgers, set in the summer of 2000.
Guinness Record was by Sonny Shum, he scored 29,090.
Of course higher scores are possible, but I think the limit would be around 200K. Over 2 million is pure BS.