I am in the midst of installing one now on my build. It is a CR Laurence 22" x 38" and it seems well made. I can make it work but the curve has worked against the contour of the teardrop body.
I have some pictures in my build journal and will be adding more later tonight. Those pictures are from last June but I worked on it just yesterday. My plan is to use the sunroof frame to clamp the roof skin before I attach the skin to the teardrop frame rather than fight the sunroof fitting to the skin after the skin is attached. I'm thinking I'll also need to add a removable screen to keep the sunroof open or off at night to keep the bugs out. It has a lip in the inside edge of the aluminum frame that I may be able to use, or perhaps I'll do something that attaches to the ceiling outside the bounds of the sunroof frame. That is a detail I'm not ready to work through yet until I get the bigger things installed.
I got it from Amazon and it was shipped by a company that seemed to be out east but the thing arrived quickly (I live a few miles north of Seattle) and its shipping info showed it as coming from Tukwilla WA, just on the other side of Seattle.
If I could do it over again, I'd consider a sunroof that curves in the same direction as the trailer body contour, or plan to install it in a flat area of the roof. The sunroof has a curvature left to right with the center being about 3/8" higher than the far left and right, and there is no curvature fore/aft. Meanwhile, my roof has no curvature left/right, but about 1/2" fore/aft since it right where the front curve of the body starts to descend.