In most states there is NO SUCH LAW..
There is a federal law, but your state may not enforce it.
You need to check with your state's laws...specially if the vehicle is going to be driven on public roads.
You can't pay to have them removed, like at a shop, but you are free to remove them yourself, and if u want u can put in a custom steering wheel with no airbag....but your insurance rate may go up!
And if u get into an accident and your vehicle originally had airbags but you removed them...u could be in trouble.
There are tons of custom cars out there with no airbags in their steering wheels, especially OFF-ROAD vehicles!!!
Hell cars in NASCAR dont even have steering wheel airbags!!
It all depends on your setup.
My uncle has a custom 95 Corvette...with no steering wheel airbag..he has a custom steering wheel..
Also, check with your state to see what is required to be a legal road worthy vehicle.
Here in Minnesota, its crazy, there is no law that says your vehicle has to have a windshield, but it if does have a windshield, it must have windshield wipers!!
But i think there is a way to file "EXEMPT" on certain things, federally. If you were to build a brand new custom hotrod, you must have certain thing to make it road legal, and airbags are not one of those things! So you can build a custom rig with no airbags, but you cant legally take an already built rig and remove the airbags, well yeah you can, u just have to file alot of paperwork, lol.
For more info:
http://www.nhtsa.gov/cars/rules/adaptive/Inoper/Fre_ask_Ques.htm