I'm very impressed with your Soundplane. It is exactly what I had dreamed to achieve by using off the shelf pressure sensitive touch pad technology. But as I read on your DIY section it would seem the sample rate of off the shelf devices today I'm presently looking at for a project of my own are too slow with Synaptics new series 7 7300 asic chip I'm reading it's max sample rate is only 100 hz. So my hopes of developing the cool $20 musical instrument touch-pad might be a ways into the future. I might take a wack at what can be done with 100 hz sample rate as that's all I can afford for now. If your interested in seeing more details of my attempts of development of an inexpensive musical touch pad see my blog at http://tactilemusic.blogspot.com/. We may not have what we need today but with your developments we can see what the future will have for us tomorrow. Thank you for creating dreams.
100 Hz is way better than 0! In other words, I think there is a lot of fun to be had and a lot to learn, without meeting any particular goals for sample rate.
Thanks for writing and I look forward to seeing what your exploration brings.