If you really want to go with the Minidisc format, check out
http://www.minidisco.com and you'll find some great deals on Sharp minidisc recorders. Sharp's minidisc recorders are actually better suited for setting recording levels and recording than the Sony's. As for microphones, go to
http://www.soundprofessionals.com. I've been using their services for customized and off-the-shelf microphone systems. They're great people and they offer quality microphones and portable preamps (if you really need them) that work very well with portable recording systems. Give them a call and explain what you need and they'll provide a high quality Audio Technica, Shure or AKG microphone that can plug-in directly into a Minidisc recorder or any other recording device with plug-in power.
Personally, I like the DAT format since I can use portable DAT recorders with digital output. The format records in uncompressed, loss-less formats unlike the Minidiscs which actually employs some form of compression and dithering. For most people, they can't hear the difference between Minidisc sound quality and CD sound quality. DAT recorders like Sony's PCM-M1 are pretty expensive (about three times the cost of a Minidisc recorder), but it is actually professional equipment and built to last. It also contains a preamplifier which allows you to use lower output microphones without having to buy and carry a separate mic preamp.
For recording in analog format, I use a Sony professional Walkman that has a Quartz-locked drive mechanism, plug-in microphone power input, recording level meters, Dolby B noise reduction and tape type selector. I bought this little unit in mint condition through eBay for less than $100, and it's barely larger than a regular Walkman. People are amazed at the recording quality.