Took an old 42U rackmount cabinet and turned it into a dehydrator, last year. Cleaned it out and used light diffuser grille for shelving, a little table fan for air movement and a simple speed controller. Ugly fruits make great dried fruit snacks.

Software may become involved. i'm playing with ideas for adding temp / humidity sensors and putting the fan's speed under the control of something that switches it based on time and those sensor readings. The in/out vent baffles could be actuated by servos. It completely lacks blinkenlights, which deficiency keeps me from showing it off more.