I was bored last night so spent a bit of time looking at the National Library and Old Maps sites to
see if there was anything marked on any old OS maps for the area but they show nothing in the
way of "Standing Stones" etc.
An exhaustive amount of "Googling" also reveals nothing.
Perhaps it's just a bit of local folklore - like the Wallace Stone of Riggend which was
mentioned on here a while back...
viewtopic.php?f=15&t=9017Unlike the Boyd Stone, the Riggend Wallace Stone is actually still there though.
You have a believable story and no stone but at Riggend it's quite the exact opposite.
Good luck and let us know if you find anything.