If you can find one (sorry, you can't have mine!), a Hohner Pianet T, dating back to the 1970s, would probably suit you.

It's unusual in the way the notes are produced - there is a set of metal reed-like flat springs which produce the notes, and the sound is produced by means of a rubber sucker attached to each key. At rest, the sucker is attached to the 'reed', but when you press a key the sucker lets go of the 'reed' and it sounds a note. It's quite piano-like in timbre, and there are passive electromagnetic pickups similar in principle to a guitar pickup that can be used to amplify the sound.

Mine is a work in progress - some of the 'reeds' have rust on them, so it isn't quite in tune, but the suckers seem to have survived okay.

I'd say it was a little louder than a clavichord without any amplification, but there are no fancy electronics to mess you up!

A problem with clavichords that people tend to overlook is the fact that one string may be used to produce more than one note (fretting) - so they aren't always as polyphonic as you might expect. If a clavichord is described as 'unfretted', it has one string per note.

A clavichord produces its note by means of a 'tangent' on the end of each key striking the string and defining its sounding length - the distance between the bridge and the tangent. It also allows the player to produce a small amount of vibrato, unusual in acoustic keyboard instruments. The strings run long the length of the keyborad, rather than perpendicular to it, which facilitates 'fretting'.

The Hohner has no such limitation - you could play every note simultaneously if you have an appropriate plank of wood with which to do it!

It must be the 'T' model (finished in black leatherette rather than polished wood), though, as earlier models weren't fully passive.