So, this isn't a recipe as such but this is what I do when I make roast veg lasagne and it always goes down well:
Roast one butternut squash, two red peppers and an aubergine, all cut into approximately 1" chunks, tossed in oil and with a couple of cloves of garlic in there. This normally takes 45 minutes-1 hour.
Make a tomato sauce however you like to do so (I use two large red onions, two tins of tomatoes, some tomato puree and a dash of balsamic vinegar, onions fried off first and then all simmered together for about 1/2 an hour, then blended with a stick blender)
Layer up with a third of the sauce, half the vegetables and then 1/2 a log of the soft log goats cheese (the Caerphilly sort, not the sort that comes with a rind) scattered over, then pasta. Repeat. Put a third of the sauce over the final layer of lasagne sheets, then tear a ball of mozzarella over the top.
Cook for about 45 minutes. Serves four greedy people or six restrained ones.
Obviously you could mess around with the vegetables according to your own dislikes (those are our three favourite vegetables, especially roast). Because you don't have to make a bechamel it's much quicker and easier, and I think quite a lot nicer.