CP, if you really want to DIY then get yourself an Analog Devices TigerSharc development system and go for it. You can do whatever you want, except you won't have access to Eventide's "secret sauce" algorithms… You will have to roll your own!
http://www.analog.com/en/processors-dsp/products/index.html
I did some of this kind of thing on an older BlackFin some years ago.
