Looking for a kit something like an Aeral Atom

I like the concept of the Ariel Atom (I know I misspelled the name in the title, but cannot figure out how to change it) but roughly $80,000 is a bit steep for this car.  I have always wanted to bulid a car though. Can anyone recommend a kit that is something like the Atom or an Ultima Can Am (but with a 4-cylinder and not as expensive)?

Thanks,

Mike