For those not using right angled valve stems on their rear tire, here is a tool to throw in your tank bag. It screws onto regular valve stems so you can reach them better. Says do not leave them on for riding, for obvious reasons.
http://www.pashnit.com/product/cyclepump.html#extension
No I have not tried it out myself.

http://www.pashnit.com/product/cyclepump.html#extension
No I have not tried it out myself.