Some synths have an option for "random" for LFO shape (as opposed to more popular sine, triangle, saw etc). Send pitch to that and tweak the speed of the LFO and you've probably got most of what you want. No glide... some synths call this Random-Hold versus Random-Glide. Being able to break apart the harmonics (i.e. additive synth) editor can go a long way toward getting the EXACT sound you want but I suspect on a mobile device that part won't be something you spend a lot of time tweaking. I could create a few WAVs for you if you want, but I'm not sure its exactly what you're seeking so I thought I'd describe the technique first.
Update:
Decided to play around with this and come up with a few samples, may not be exactly what you want. Keep in mind they are 15s each so you might want to chop them up to keep only parts you want, as the note duration has been randomized here as well as the pitch.
http://www.mediafire.com/?7juux98zbm...1zgy04qj72sncz
I used Zebra and I actually use two LFOs here. One for the randomization of the note tune itself, and a second one to vary the rate of the first LFO (so there are shorter and longer beeps).