The instrument you describe does sound like a cittern.  The scale length could be a problem, but the cittern/mandolin family does include smaller instruments that perhaps might serve; it's worth having a look at these two sites for more information:

The Cittern Pages
Han's Irish Bouzouki Homepage

Open tunings are used quite a lot (perhaps why the chord-patterns you saw were unfamiliar), which of course makes it possible to play -for example- accompaniment using only a couple of fingers at a time.  String tension tends to be relatively high on these instruments, but I know people who play cittern guitar-style, much looser-strung than I would, and it sounds fine when they do it.  Good luck!

Malcolm