I have John Allardyce who married Elspet Cuthbert, daughter of Peter Cuthbert in Keith, in Huntly on 19 August 1816. John died 18 May 1868 in Gartly. I don't know where he was born but could he be one of yours?
I am also in touch with another descendant of the Rhynie Allardyces. If you would like to contact me privately with your e-mail address, I'll pass it on to her and ask her to get in touch with you.