According to the state of CA, following are prohibited to form an LLC
A California limited liability company may not provide "professional services" in California. (Section 17701.04.) "Professional services" are defined as any type of professional services that may be lawfully rendered pursuant to a license, certification, or registration authorized by the Business and Professions Code, the Chiropractic Act, the Osteopathic Act or the Yacht and Ship Brokers Act. (Sections 13401(a) and 13401.3.) If your business is required to be licensed, certified or registered, before submitting Form LLC-1 to the California Secretary of State's office, it is recommended that you contact the appropriate licensing authority in order to determine whether your services are considered professional. For licensing requirements in California, please refer to the CalGold or California Department of Consumer Affairs websites.
Also I called CSLB who issues a contractor license and they have no problem issuing to the LLC, please check theis link and requirement to apply for a contractors license: http://www.cslb.ca.gov/About_Us/LLC.aspx