For pitched percussion type stuff, you might want to consider Kontakt. I have used it for Kalimba, Kora, dulcimer/santoor type sounds on Zendrum. I also have a set of Hang Drum samples (a Kontakt "instrument" or sample set) that I'm very fond of. Kontakt may be overkill for what you're looking for, but its a really great software tool. Kontakt comes with a big library with lots of great stuff - including guitars, pianos, organs, synth stuff, and some tasty percusssion kits. I am also very fond of Battery 3 - which is also from Native Instruments - Battery 3 is a percussion oriented sampler that works well with Zendrum. Battery is great for customized percussion "kits" - but I'm not sure how much pitched percussion there is in its large library.
you will have fun with your zendrum