I asked the same question about ours 11 years ago. Came up w/ getting some "J" channel, plexi glass. Cut the "J" channel to same size as skylight. Cut the plexi glass to a tad wider than the width between the 2 "J" channels, then slide the glass into the channel. To block the sun, just get a window cover that would fit over entry door w/ the velcro and slide on top of the glass (don't velcro it to anything). There is a 1" gap or so on BR side so I just stick a toothpaste box under it. Blocks out a great deal of light, but not entirely. If you want light, simply remove the cover from top of glass.
The shower and sink are "part" of the bedroom and an accordion door separates the 2 if need be.
If you PM me your e-mail, I can take some pics and send to you. Phooey, just remembered my son is out of school and he might be able to help me take/post pics on here (I'm 'puter illiterate!!)