Unfortunately, I think you'll be waiting a long time. Support confirmed to me that there is no further development on the StringPort!!! Likely that they haven't been able to write good quality 64bit drivers and are therefore devoting their time to other projects.
This sucks, there is so much potential with the StringPort but currently so much of it doesn't work well at all.
I have found some half decent audio-midi software, finally. http://www.jamorigin.com/midi-guitar/Wi ... index.html
works rather well, even decoding polyphonic audio from a mono signal, so at last there is a half decent solution for driving VSTi's