I have only met one [name_u]Ellis[/name_u], and he was a little boy, about two years old. And even besides that, I have never thought of [name_u]Ellis[/name_u] as a girl’s name. I would definitely consider [name_u]Ellis[/name_u] for a boy; it happens to be on my long list! [name_u]LOVE[/name_u] it.
[name_u]Madison[/name_u], though, despite it’s surname status, has been so overused for girls and pretty much never used for boys, so I do perceive it as more feminine. However, there are a lot of surname-type names that are far more popular for girls that I happen to much prefer for boys – [name_u]Madison[/name_u] just isn’t one of them. I personally have never cared for the name for either gender; it simply does not appeal to me at all. Still, I think it would be a bold, but not crazy, choice for a boy today because, as said above, most (not all, but most) names that end in ‘son’ definitely lean boy.