booster seats and sculpted rear seats

[SenoraPartridge]

is there an easy way to fit 3 booster seats in the back, even if your car has sculpted back seats? or is the only way to buy a car with a flattish back seat? can I buy narrow boosters? or a booster with a slanted peice that fits underneath?

anyone?

wish I had some money - think there is a definite gap in the market here for a bean-bag type curved seat adjuster.