Just to follow up - I did buy the Sidi size 39s from someone on this list, and they fit PERFECTLY! They are a bit smaller than my Lake's (also size 39), but are just right, and I've had no numbness at all from them on rides of up to 50 miles. I almost always got some foot numbness on the right foot with my Lakes, perhaps because they laced up. I can see where the 39s would be too small for anyone with a size just a smidge over 7, or with wider feet (mine are on the narrow side) as they couldn't be a bit smaller and still fit me.

Thanks for all the input!

Emily