I'm certain Zen Studios has a team of experts who wrack their brains coming up with all of these excellent tables, but I figured it couldn't hurt to throw a few ideas their way in a helpful little manner...
After a friend of mine played Zen Pinball 3D he suggested the Terry Pratchett universe would yield up a good pinball table and I had to agree, with things such as giant trolls, Rincewind's luggage devouring the ball and scampering it around, Death narrating the game, knocking the ball into a nest of Nac Mac Feegle, having a central area that opens to reveal four elephant bumpers, missions such as delivering mail for Moist von Lipwig by hitting the ball through orbitals, helping the Watch put out Ankh Morpork when the city catches on fire, working for the Assassin's guild by hitting drop-targets, gathering ingredients for a witch's brew, etc.
2.) Jules Verne
I think the world of Jules Verne could make an interesting tiered table, with the top of the table being the sky, the center being divided between the land and ocean, and the bottom being the center of the Earth. So you could launch your ball into Robur's airship (Master of the World) and Mr. Fogg's balloon (Around the World in 80 Days), in the ocean you could bounce the ball off of tentacles attacking the nautilus (20,000 Leagues Under the Sea) and then drop into the caverns and avoid magma and dinosaurs (Journey to the Center of the Earth) and even the backboard could become part of the table like in the Paranormal table, allowing you to send your ball up like a rocket into the eye of the moon (A Trip to the Moon).
3.) Dead Times
It seems a little cliched these days, but a zombie apocalypse table sounds like fun, with the back-end of the table made up as the chaotic city and the foreground set up as the countryside, with a network of highways connecting the two which would get blocked by panicked traffic. Events such as meeting up with a helicopter via hitting a certain building, rescuing trapped victims, making a run for supplies... it could even have elements of survival horror games in which you get points for keeping characters alive by making tricky shots to get food, ammo, and medicine from the dangerous city.
4.) Mushroom Men
I noticed in your 'other games' section Mushroom Men was listed, which I thought was a pretty terrific game with a great aesthetic and unique design, and since mushrooms tend to lend themselves naturally to be pinball bumpers, this one just sort of writes itself. Come to think of it, I've yet to see a Zen Studios table that makes use of the 'shrunken perspective' gimmick, with larger than life objects making up the table (thimbles, tin cans, etc.)
5.) Super Mario Brothers
Since you've got the 3DS distribution, I'm salivating at the thought of a Zen Studios Mario pinball table, filled with warp pipes, goomba targets, mushroom bumpers, pirahna plants, power-ups, etc. I can already picture a mission involving repeatedly hitting a target several times to power up Mario to allow him to defeat piranha plants blocking pipes, or in a move similar to the Golden Bridge from the El Dorado table moving a pinball along a Mario Bros style world to reach a flagpole at the end.
Anyway, if nothing else hopefully this was all just entertaining to read. Keep making those clever tables guys!