Hi,
My Uncle's Y-DNA haplogroup (certainly amongst anyone who has tested) is very rare and does trace back to Scandinavia) - he is proud of his uniqueness!

Agreed that line is unlikely to show up in the autosomal DNA as the Isted's have been here for so many hundreds of years but I have a couple other branches of non-Isted in my tree, which are more recent (last couple of hundred years) that are from northern Germany / borders of Denmark and which seem to have disappeared from Ancestry's list - on both Mum and Dad's side.
Liz