Looking at the fingering chart on the manufacturer's web-site
http://www.xaphoon.com/fingeringcharts.html it would seem a diatonic pattern is (almost) available in the key of C until you get up to B ... so not quite an octave, but may be worth considering if you already have an instrument. Personally I'd block the unused holes with beeswax, no chance of a leak and looks neater (traditional, even!)
If you're looking for something a little "different" and have yet to make a purchase I'd suggest a "chalumeau", basically a keyless clarinet, available economically from Hanson
http://www.hansonclarinets.com/Hanson_C ... umeau.html or in wood from several other manufacturers at varying prices. I have a Hohner "Pocket Clarinet", much the same thing ... it's a lot of fun
