exactly, I never had ricotta/mozarella filling, but to me that sounds good..;o)
but back to your question:
many possibilities... I usually have a two-sauce-lasagne.
one layer with a kind of bolognese, that means with grounded beef and the next layer with bechamel and peas...
you can use some fried bacon with the bechamel, too, maybe instead of the bolognese, or add other veggies to the bechamel, just as you like
LiGruess cara ~~~ Life should NOT be a journey to the grave with the intention of arriving safely in a well preserved body, but rather to skid in sideways, chocolate in one hand, wine in the other, totally worn out and screaming "WOO HOO what a ride!"