the good thing about an excalibur is that it has temp settings so you can make it a little warmer to dry thicker things, kuj. but you are slightly cooking it, which might take away from the idea of prosciutto.
the salting of the pork for prosciutto along with the method of drying/curing ensures a fatty-moistness to the delicate flesh.
to use a dehydrator, you'd have to slice it somewhat, and then you'd be making duck jerky. good, but maybe mot as tender.
good luck. can you post pictures of your experiments? i'm very interested.
The past is gone it's all been said.
So here's to what the future brings,
I know tomorrow you'll find better things