When I have a large area to paint I bust out my power roller. Def the way to go. Actually have 2 of them. They take a bit to clean (run soapy water through them for about 30 minutes) but that part is automatic. Even after doing that the pump lines clogged but the entire unit is so easy to service it takes me 2 minutes to clear the clog. Well worth the money. At first it starts painting a reverse hole punch but once you figure it out you can just keep going. Protip is to not hold the button the entire time after the roller is saturated with paint. My friend bought one and complained that it pumped the paint too fast so figured I would mention it.
http://www.wagnerspraytech.com/products/rollers-pads/rollers/smart-power-roller-system/

Mine is older and can actually work with a larger paint can as well. I cannot imagine that the sidekick would not work. Just be sure to wash the roller between uses as they are expensive and no one seems to stock them. I have used the same roller for 8 painting sessions in different colors and it is still holding up. Just just make sure when cleaning the system to clean it for a very long time. the water should come out clear. You still may have it glue the pump line shut but like I said, it is a simple fix. If you need any info hit me up with a PM.

edit: Also they used to make ones that have two handles so that 2 people can roll at the same time. If they make the sidekick like that definitely get that. It took 2 coats with killz to cover all of the sheet rock well enough to paint. Painting I can usually get by with just 1 coat. That thing uses so much less paint but gets way better than traditional rolling.
Also be sure to use the "splash guard". It really cuts down on mess.