Rather than waste the time looking up a baked spaghetti dish, I just made one up with what I had (which included Costco organic frozen vegetables, half an onion and a few other things, along with the obvious mentioned already, and the obligatory whole wheat spaghetti and tomato sauce). R. and I disagreed on a number of points (notably, the amount of tomato sauce required) and I just went and did it the way I thought it should be done. Inevitably, I then had a pan selection problem, because I'd overshot the 9x13 option. Severely. Which is good. I got out the roasting pan (anodized aluminum) and R. concluded it was non-reactive. I wasn't going to argue. I figured, these things are inevitably about an hour in a medium oven.
One tip for anyone else trying this: check periodically and poke back down any pasta ends that poke their tips above the saucy goodness -- they'll burn otherwise. Usually there's cheese on top to prevent this, but I don't do cheese and R. only does some.
I had it reheated for lunch (after freezing half and R. taking some to work for lunch) and indeed, it is teh awesome. Can I tell you proportions? Heck no. It was about a pound of ground beef, 2 italian sausages, 1 box Pomi tomatos, 2 cans bionature (the bigger of the two commonly seen in grocery stores, but not crazy large industrial size) (this would be what I had, not what I would have gone out of my way to pick) , 3 cloves garlic, some spaghetti, some dried thyme and basil, some fresh ground black pepper, half a large onion, 2 bell peppers, 1 1/2 packages white mushrooms and an unspecified quantity of frozen mixed veg. The technique was about what you'd expect: saute the veg in olive oil, mix in the meat and tomato sauce, sprinkle on the spices, add the spaghetti (hey! cook it first! maybe leave it a bit al dente), dump it in a large dish. If you don't have a bowl out to combine it, you can try combining it in the dish, but that will tend to leave patches of uncombined pasta (I know -- I saw it when I was moving some to freezer containers).
Every time I do this, I remember why I don't cook: children underfoot complaining about this and that and demanding something else, usually non-verbally so it requires serious sleuthing to figure out what is needed.