I'm not a fan of lasagna with ricotta or tomato sauce. The only lasagna I make is alla bolognese with paper thin spinach pasta. It ends up layered like a baklava and melts in your mouth. It's an all-day affair. It's based on a Batali recipe, but I can't find a recipe online that matches my workflow. They're all dumbed down too much, especially shortened cooking times for each stage of the Bolognese prep, the use of frozen spinach in the pasta, and how the vegetables are too large a dice for the soffritto. I prefer a very fine bruniose that disappears in the final sauce. It's frowned upon, but I'll use the food processor if I'm feeling lazy. I forgo the pancetta, and use a beef, pork, veal blend.
If you really want to get crazy, try Bugialli's Bolognese. It's like four or five pages of very fine print.
All kinds of lasagna interest me, including the type you describe. I have not experienced a big difference in green pasta whether the spinach is frozen or fresh. I find frozen to be more predictable but would use fresh if I had some on hand that may go to waste. In that situation, in fact, being faced with wasting fresh spinach could be enough to motivate me to commit many hours to making lasagna.
I’ve had some nice results using, as you said, paper thin spinach pasta with many layers alternating with mornay sauce. There are a couple of soups I make where I use a fine brunoise dice because I like what they contribute texturally. Taking it up a notch, I like to color them up by flash frying (I should try roasting), which adds another layer of flavor as things break down.
