Yes thats very true, it does raise the question of the pictish being a celitc, pre celtic society or something else entirely different. A new history of the picts by Stuart McHardy is supposedly a good read. I do feel as a wargamer there has to be something for them at some point lol. Same for the Irish. 

I'd suggest anyone interested listen to this.  http://www.bbc.co.uk/programmes/b09cvx7b

These are brilliant programmes in general, with experts in their field sharing their knowledge.