WSD frames seem to be for women who are shorter than about 5'3". After that, it just doesn't scale up, since the short torso effect seems to be more pronounced in shorter women. At 6'1" I seriously doubt there are wsd bikes that would fit her as I don't think I've seen over a 54cm wsd frame, and that would be ridiculously small on her. A non-wsd bike could fit her just fine. She might have to swap out handlebars since even at that height a woman is going to have narrower shoulders than a man of the same height. I ride a 56cm trek pilot 2.1 at 5'8" (funky leg geometry demands it), and the bike came with 44cm handlebars(note: I have drop bars, not flat bars, as I find flat bars give you no options to shift your hands around and lead to numbness and pain as a result). Had a lot of neck and hand pain, which disappeared when I swapped to a 40cm handlebar. Those issues will probably be exacerbated by her height, so make sure she hits a reputable LBS who will fit her properly and do what it takes to make the bike comfortable for her to ride whether its 2.5, 25, or 250 miles. REI is fine for people who don't have any special requirements, but at her height, your friend should definitely visit a real bike shop, as they will generally be a lot more able to outfit her with the bike that will really work for her.