As long as it is only for home use, you could probably get away with including "arcade greatest hits" pc ports.
My x-arcade came with a few discs of them. I never messed with those, but I know Midway's collection allows you to launch games by individual exe, which means they can be launched from a front-end. Just add -f to the command line to get fullscreen. That collection includes Mortal Kombat.
Although not legal, nobody is going to come after you for selling one cab locally with everything included.
Listing it on ebay or selling them as a business...not so much.