High Pressure Valve Stems

I'm looking for some high pressure valve stems for my trailer tires and I'm getting the run around with the local tire folks...

I need a long valve stem (say 2") that will handle the 80psi that's in the horse trailer tires. DT has the high pressure ones, but they are about a 1/2" long and wont clear the wheel covers.

Anyone know where I can buy a handfull of these to take with me when I go get my tires replaced?

Thanks!

Somewhere that works on tractor-trailer tires?

Thanks for all the replies (online and offline)...

Al Cavan pointed me towards to Gebos in McKinney.... I'm going to stop by there this week and see if I can pick some up.