A piezo pumps will help SCALE IT VERY WELL .I hv seen the similar pumps from some webs like:[PLAIN]www.takasago-elec.com[/url] , http://www.piezodata.com ,
http://waterpumpsz.com/2675-micro-water-pumps.html , I think u can find one suitalbe for yr work .
I'v ever one time saw one introducing article on the peizo sensors application from one web . It has a quite detailed data sheet on it ...Hv to recall the memory ...seems frequency decided the sense like that .