I have a whole wall that I need to block off with some sort of door. I'm thinking that a bi-fold door would be awesome. However, my husband kind of wants a sliding door. I just think how cool it'd be to have a whole wall made up of a door that could easily be tucked away when needed. This would make outdoor barbecues a lot easier. It would sure save me from having to open the door every time. http://www.superiorwindows.com.au/content/Products/BifoldDoors.aspx 

Wow I too have the same glass above my doors. Mine are all internal swing doors therefore I don't have your delema. I'm in the middle of renovations and mine are staying. My walls will be dark and modern with all the trim white with the original character and it looks great. With your wall, it's a lot to deal with therefore would suggest replacing the slider with a glass door with timber trim, keep your walls light modern and bright and paint your trim dark (any colour you favour) here is my example to give you an idea of what I'm talking about hopefully you can see the value here is a snippet of my renovation good luck....hope my idea gives you plenty of ideas

FormFunctionNT I love your lego door! So innovative. This idea may be a little busy for the other door, but just putting it out there... You fill it with squares of the 4 colours, but randomly leave 4 blank. Almost like 4 have left and moved 'next door' if you'll pardon the pun! Sorry, I couldn't help myself.

Should be possible to reroute the wiring and if you are relocating the towel rail then it’s even better. If not, whomever installs the cavity slider just needs to be aware that you want the towel rail to go back in the same spot. They may have to add a few pieces of timber into the cavity slider before it is gyprocked. Hope that helps.