Mountaineering boots and gloves could allow an avatar to move across vertical terrain. This could help ground locked miners and hunters access remote places and provide convenient escape opportunities from mobs. It would also be fun to go mountain climbing in the game.
Though this is a good idea I doubt that the system currently supports something like this or that it will ever.
If it was an item that you had to equip and decayed as you climbed, I bet MA would be more apt to consider something like this... Great idea, though.