Try contacting the following people:

L.P.Lee, S.A.Berger, L.Pruitt, D.Liepmann
Berkeley Sensor and Actuator Center
Dept of Mechanical Engineering
Univ of California, Berkkeley, CA 94720

I was at a conference last week in Banff, Canada where they presented a paper
"Key Elements of a Transparent Teflon Microfluidic System"  which showed a lot
of techniques for making MEMS devices with silicon.

I hope this helps.

John West