Have you considered a Maxpedition Single Sheath? You can see some pics of one containing a Wave here on BCUSA. Not as nice as leather but it will securely hold it to belt or pouch and with a full length velcro closure there is little chance of it falling open when you are working at height.
Rob Evans could do you a very nice version, but I think he's in the middle of a trip to Sweden at the moment....Hi all,
Looking for someone to make me a pouch for my Leatherman Wave (tried the Leatherman ones and found them to be all lacking).
I'm a tree surgeon so my knife is with me every day, any advice most welcome.
Cheers
Dawsie