As well as Cullen, that Sean menationed, a few more courses up north that are conmfortably under the 5,800 yard cut-off and include Newtonmore, Kingussie (both about 5,500 yards), Grantown on Spey, and Huntly. I'd be happy to recommend any of that lot for a bounce game on holiday. Down in the central belt there's Whinhill at c.5,500 yards which is definitely worth a play if you enjoy old time golf.
Niall