I've already got some Phil! I bought them at Godmanchester CCC National a few years ago on a lovely-ish summers day ( memory embellishments) still in their box for a fiver. I've used them once!
These days I just throw the skis in the back but perhaps as the kids grow and get into it I'll have to put them on the roof. They take three sets of skis - slightly bizarre. Four? No three.