If I wanted a more or less as-new 486 system to run old DOS stuff on, what are my options? Are there companies that do custom builds, possibly in a more modern case, or places I could get unused components? I've considered this as a project for a while, because DOSBox only satiates my nostalgia to a point.
I wanted to do the same thing but not deal with too many old parts. There are a bunch of single board computers with clone x86 pentium-ish cpus available all on a single ISA card, so I plugged one into ISA backplane, added a vintage VGA and SB card, and wrote a TSR that uses one of the watchdog timers on the board to slow it down a bunch so I could play Wing Commander II again. It’s a fun and not terribly expensive weekend project.