I'm not sure when we plan on getting more Xbox 1 stock as we have quite the selection still. The blue candy may or may not come back, it was a special hydrodip from a company that might have gone under. I'm not sure if they are no longer in business or if we had issues, I just know we haven't gotten anything from them since.
The "handkerchief" shell is actually my favorite, but no one seems to like it. Blue circuits looks like a really dark navy from further than 2-3 ft away, the closer you get the more you can see the details in it.
If you're holding out on buying hoping to get different shells I wouldn't advise it. It has been a long time since we've gotten any and I don't think Odin plans on getting any more until our stock runs really low.