The tip-out I drew up in that thread was based on the premise of the whole 6' of the bed being adapted for sideways sleeping. But, it could certainly be altered for a 2' area.
What you need to consider is how high your interior is going to be as well as how wide the trailer is going to be. And how much height you have along the curve in the bunk is going to be in the rear.
If you're looking at a 5' wide trailer, your opening for your tip-out needs to be 1' high to give you 6' in length when opened. Assuming you want at least 1' of foot room underneath the bunk, you can't be back any further than a point where there is less than 2' high along the curve of the roof.
It's one of the things I needed to consider when figuring out what profile to use. I couldn't do a 6' wide, 2' high tip-out with a lot profiles. There simply wasn't enough height with some of them to do it.
A slide-out would also be 1' high, but the downside is that you pretty much have to have the slide out pulled out to make the camper usable. Where, with the tip-out, if you do the collapsible sides like I drew up there you can still use the bunk for kids or even for storage with it closed.
It's all a trade-off of one type or another.
I had considered a slide-out but could never really figure out how to seal it properly without the top of the slide-out sloping down. Others have done it, so, obviously it can be done.