There is a client library for Presto - see http://www.aocate.com/presto/ - so it would be great to be able to access this from the Subsonic app. I've downloaded the source for the Android app and have been playing with it - happy to look into doing this myself and send back the patch to you, if you'd be happy for me to do that.
I use Presto extensively for listening to podcasts - in general I find speeding up the voice by about 1.3 x allows me to still follow the speech effectively and get more podcasts into my free time. An immense productivity booster.
I'd like to move my podcast collection from the podcast application I use on my device to the server, and get the podcasts as and when I really want to listen to them - saving me about a couple of Gb on my device!