I've built 2 of these for friends.
http://www.arcadedepot.com/HTML/kits.html
Very good quality materials, Ms Pac dimensions, total cost ended up right around $1K depending on which controls you use for everything minus the PC, which doesn't need to be very powerful unless you want to run modern games. Going this route is, in my opinion, the best-case scenario, since you can do the entire project without actually using any parts from real machines, which is ideal. Having said that, the last time I built one, brand new arcade monitors were still available for about $300, that's no longer the case, so it's either find a used monitor or put in an LCD. An LCD would mean you don't need a fancy video card, so it would make it considerably cheaper (maybe $300 or $400 less), though in my opinion it's not worth doing, it just doesn't look right, though many people don't mind it. Also if you don't need a coin door that's quite a bit of savings there too.
If you're handy with wire stippers, you can definitely DIY and do the entire build without having to use original parts at all (except maybe a monitor), though configuring MAME can be tedious.
BYOAC.com is a better resource for this type of stuff.
I'm happy to build one to your specs if you don't mind shipping though it would take about a month of weekends to do.