The portable minidisc will have one stereo 1/8" mini-plug. It will also have one optical digital in and one stereo 1/8" mini-plug line in. Though the last two are being combined into one on the newest models.
To find these portable stereo minidisc units go to the specialized electronics stores downtown. They have stuff like this.
Stereo mics vary. Look at the options and listen to the recording quality. They will be small for these kind of units, and have two mics at an approx 90 degree angle joined together within a plastic case.
Sony, Panasonic, Kenwood, JVC and perhaps more make these little units. Some use recharable AA batteries some use specialized batteries. All come with an AC/DC wall plug adapter and some tiny cheap headphones.