I'm looking to make a gear shifter which is as light as possible. I also like the simplicity of a "thumbie" shifter. I've found these http://www.b-t-p.de/B-T-P_Team/products ... fting.html
(About half way down the page, its the carbon downtube shifter). Does anyone know if I were to just buy a Paul's components mount, could i fit the carbon shifter straight to it and go? Its all very confusing!

Aren't the Pauls mounts different for Shimano and SRAM? It might be worth contacting the company and asking, once you know then I imagine it would fit on the correct Pauls mount.

It looks like you could.

Carbon Fibre Downtube Shifter
Front and Rear Derailleur Compatible. Non-Indexed.

But won't you lose more time with crunched shifts than any weight-saving is worth? : )

And yes, Paul Comp mounts are different for Sram and Shimano. I've got some Paul mounts with D-A barend shifters, they work really well, nice and clunky, positive. But shifting is undeniably more ergonomic with std MTB triggers. I only use thumbies to create space on the bar where I want it, and to avoid bar rolls etc. One real drawback is that they're more exposed so for all the (fairly weak) durability arguments they could be wiped out in a crash.