Not much new on Flickr under "wnbr" or "naked bike ride", but searching "ciclonudista", I found out that Madrid had a ride on June 13th. Very small, very male-heavy ride, and the pictures are watermarked and not especially great shots, but there are a couple of decent enough looking women... as far as you can tell behind their masks.
Album:
flickr.com/photos/tarzandelosgnomos/albums/72157714688011141
A few sample shots of the women:
flickr.com/photos/tarzandelosgnomos/50001007313/in/album-72157714688011141/
flickr.com/photos/tarzandelosgnomos/50001532526/in/album-72157714688011141/
flickr.com/photos/tarzandelosgnomos/50001006708/in/album-72157714688011141/
flickr.com/photos/tarzandelosgnomos/50001568311/in/album-72157714688011141/
flickr.com/photos/tarzandelosgnomos/50001041453/in/album-72157714688011141/
flickr.com/photos/tarzandelosgnomos/50001817572/in/album-72157714688011141/
Better than nothing! Hey, I'm the guy who always complains about people complaining every year the WNBR is dying and the pictures are worse than they've ever been. This time, it's true! WNBR pictures will be bad this year, and I'm glad to take what I can get!