I recommend the employer-sponsored labor certification process as the quickest way to a Green Card. The PERM process has greatly reduced the processing time for Labor Certification and you may not have to wait in line to file your Application to Adjust Status.
The H-1B visa is employer-specific. In other words, your employment is restricted to the sponsoring employer. Further, an H-1B visa holder may not be self-employed. However, this does not preclude an H-1B visa holder from investing in a business or holding shares of another corporation.
You can leave and join a new employer without having to spend any time with the current one. There is no regulatory requirement that you spend any mandatory time with the sponsoring employer before you begin new employment.
In a memo dated, January 29, 2001, Michael A. Pearson, Associate Commissioner, Office of Field Operations, outlined the requirements for admission of an individual at a Port of Entry in the circumstances described in your question. The memo states that an H-1B applicant for admission, who is no longer working for the original petitioner is [...]
Accountants in the United States fall into two categories, Certified Public Accountants and non-certified accountants in private employment. Needless to say, the former category is highly compensated and enjoys better employment prospects. If you desire to acquire certification, you must pass a licensing exam [CPA exam conducted by the AICPA]. Please visit http://www.aicpa.org/BecomeACPA/Pages/BecomeaCPA.aspx for further information. [...]
The H-1B visa regulations are very clear. The qualifications for a beneficiary are covered by the regulations at 8 C.F.R. 214.2 (h)(4)(iii)(3): To qualify to perform services in a specialty occupation, the alien must meet one of the following criteria: Hold a United States baccalaureate or higher degree required by the specialty occupation from an [...]
You have a right to be paid for your services. I recommend that you discuss the matter with your employer and insist on being paid. Failing which, I suggest you contact a good lawyer in your neighborhood to negotiate on your behalf. Under the American Competitiveness and Workforce Improvement Act [ACWIA], Employers are not allowed [...]
On June 1, 1999, the Immigration and Naturalization Service published an interim rule at 64 Federal Register 29209. The rule amends the previous Service policy statements regarding the eligibility of H-1 and L-1 [there is a move to extend this to F, E and O visa holders] non-immigrants, and their dependent family members, to maintain [...]
I suggest filing an Application for Action on an Approved Petition on Form I-824, seeking to amend the Petition from a Notification to a Petition for Extension of Status. You may have to appeal to Service discretion in the process, but I think this is better than going back.
I assume you cannot file your Adjustment Application due to retrogression. The only way to obtain an extension would be to premium process your I-140, Immigrant Petition and use the approval to apply for an extension pursuant to §104(c) of AC-21.