I've begun carrying multitools horizonally on my belt, next to the buckle. The Gerber Legend MP800 is too wide to fit in most of my horizontal sheaths, except for a modified Maxpedition Volta. I don't own a Leatherman OHT or Gerber MP1, but suspect that they may not fit either.
I just bought a Red Rhino Mega Pouch on eBay. It can ride horizontally on a belt and is wide enough to hold an Altoids tin.
The Gerber Legend MP800 fits in the Mega Pouch with room to spare. I've been carrying this combination today to see how well it works out.
Here is a link to the Red Rhino Customs web page for the Mega Pouch:
http://www.redrhinocustoms.com/products.html#!/The-Original-Red-Rhino-MEGA-Pouch/p/44069621/category=0