There are other solutions apart of double-playfield to have more scroll planes.
Toki has two scroll planes in multidirectional scroll. Just the screen is a little bit small. But I remember changing the size of the screen with Commodore1084S monitor. It just looked very similar to original coin op.
RiskyWoods and R-Type2 has a second scroll using sprites.. in R-Type2 works really good.
Another good example of Amiga versatility is JimPower, the game is utterly crap, but JetPac levels are very amazing. Near the end of the game are a fire effect really cool. (I would preferred the game were just those levels and quit the ugly and stupid walking levels)