I've had about 15 bikes and most were assembled from the frame after purchase. My current mountain bike was ordered sight-unseen from a catalog. Never even saw one of any size. It fits better than any mtb I've had.
My Seven, which was custom made for someone else, was one of the bikes I did test ride, and it felt awful. It was so uncomfortable I didn't want to ride it at all, but I knew from the measurements I could make it work. Had it for 11 years now.