the 65816 is odd as it multiplex the databus and adressbus now if you think you need 16mb addresses great otherwise its a big timewaster WDC's w65c02s runs at 14MHZ without a heatsink and ive seen some run faster

parallel is easy and if you get a real oldie like my apple 2e you can make a eeprom programmer EASY plus the guy talkin bout breadboardin a comp is silly your cpu is not TO fast as you dont have to run it at top speed now do you?
my prom writer on my 2e is breadboarded and it writes a 32k prom in 1 ...