sort of like speak and spell, but with extended IPA

So I'm currently working as a research assistant on a project that is like half engineering, half music, and a tiny tiny bit linguistics (that's why they hired me), and one of my tasks is to find a speech synthesis program for IPA that lets you create segmental speech, BUT, I also need to be able to include suprasegmental features (tone and stress especially) with it. Does anyone know of anything like that?

Either an independent application or a MATLAB toolbox would be awesome, thanks. I know it's sort of a long shot, but hey, science is a verb now.