I haven't been following this thread, and I don't want to interrupt if this
isn't relevant, but I have a FANTASTIC fuel shut-off.  It's made by Peterson
of machined aluminum.  It is also integral with a very nice and fine fuel
filter.  So for the weight of a shut-off I get an easy-access, easy to clean
filter and shut-off in one.

Here's a link to the product (I have the 600 series with -6 fittings (very
simple installation):

http://www.petersonfluidsys.com/fuelfilt.html

Matt