There aren't any other carvings around - the nearest of any kind are the Braes of Foss stone way down at the bottom http://www.themodernantiquarian.com/site/1272

I've never seen the carvings at the top before in 15+ climbs of Schiehallion, so they might even have been made in the last year. Or I might just be less observant than I think! I'll go back next year when the snow has cleared and have a good look at them

Cheers
Andy