Thanks for being so responsive! :)
Actually I’d be super happy with just the original game but with (1) sandbox/endless mode, (2) slightly larger map (maybe 20-30% bigger), and (3) a “Windows 3.1 Minesweeper” kind of option where I can choose a map size and the time/resource limits will scale with it when I’m not playing sandbox mode. This way I can customize my game to be shorter/longer depending on my wishes. And what I love most about the original game is the possibility to study and mod the source code. It is the ultimate in moddability! I would pay A LOT of extra money for this game if I can mod the source code directly.