hi again,
to get an overview what kind of sensors exist, you may want to look at the digikey pages for sensors:
http://dkc1.digikey.com/DE/DE/PDF/DE051/P6.html (in german)
http://dkc1.digikey.com/US/PDF/T052/P6.html (in english)
if you see something of interrest, drop me a note and i will see how it should be interfaced...
greetings,
chris