can somebody build me this musical instruments for a modest sum:

You could functionally have this with a breath controller, any continuous MIDI or CV controller (e.g., like those found on many MIDI keyboards), and a synth that makes a sound you feel to be electric-slide-whistle-like. It's not going to look like a slide whistle, of course, but that's a lot harder. You could probably modify a real slide whistle and add the necessary controller bits fairly easily, though.

http://en.wikipedia.org/wiki/EWI

there are modules to convert pitch to midi?!?!!?

sadly, that sound is the only thing i was able to create with Max/msp before it crashes my computer. WOOHOO!

yeah. get a lavalier mic with a wireless kit and glue the mic up by the fipple. run the wireless output box into a little amp with shitty headroom or whatever. the end.

or alternatively spend eight hundred dollars as the professionals have suggested.