The thread is https://www.irv2.com/forums/f258/thinking-of-adding-a-roof-deck-524611.html and it was post #20.What, really? Do you remember where you saw this?
A couple updates. I bought one of those telescoping ladders, and I think I might just double it as the loft ladder, replacing the old one. I'll have to see how that works out.
Something I noticed though when I was on the roof was that the loft skylight does indeed have a hinge, which allows for at least cracking it open. I didn't want to test it out, since it was around freezing temperature, and I didn't want to risk breaking any brittle plastic due to the cold.
I might go back when it's a bit warmer to see if that hinge can open all the way, or if it's designed to only crack open.
Having an escape does sound like a good safety feature on top of how I'd like to use it. Having another viable escape can be a good thing for a number of weird, but rare scenarios I can imagine up if I let my mind wander a bit (zombie apocalypse anyone?).
Google "Bus escape hatch" and look at images. That may give you an idea.