I've know a person that imported his car directly from a dealer in Japan. He had no problems except for the extra $$$$ he had to pay but the dealer in California contacted a Japanese dealer in Tokyo and did some paper work and was shipped along with other Nissans bound for the US Market. Went through the customs with no problems since it was being shipped to the dealer directly. He got his car and is the only one with a RHD Skyline GT-R R34 V-Spec II M-Spec Nur brand new. None of that Motorex dealer crap. So yeah, you can. There are loopholes, you just have to find it.
here in So.Cal. (Sounthern California) I see a lot of JDM spec cars. I've seen couple of RHD DC2 Integras, Civic Type Rs, MR2s, Supras, Skyline GT-R R32-R34, Silvias, and even a Nissan Laurel. So anything is possible if you live in So.Cal.