Check the albums section of the group; there have been pop-top eggs!
The first problem is to find a place to cut the egg where it doesn't interfere with window openings. The second problem may very well be finding a way to reinforce the entire egg because it looks like it depends on the roof to keep its shape.
It might make more sense to loosen up the lower cabinets/closets, cut the sucker right around the belly band and glass in an entire strip all the way around, making it permanent, not pop-up. Have to add a section to the door or to the top of the opening.
I've assumed that I'd have to reinforce the roof ... I think stretching the belly band is a bit beyond my technical skills... no, let's say that's WAAAAY beyond my technical skills. I have added a pop-top to a '65 Dodge van, so I've got some idea what's involved there. I'm also interested in keeping the wind profile from getting too high while on the road.
It seems that there's a straight rectangle w/ no cabinets in the way around the raised part of the stock roof. I'm not going to experiment on my egg, as it's been in the family since it was new ('72) but if it's been done before I'll gladly follow someone's footsteps.