1. I worked on L1B till AUG-12-2013 have salary slip till AUG-12-2013 date. Worked on L1B status 3 years and 24 days. Applied for H4 before leaving L1B Company got the receipt before AUG-12-2013.Also Have past approved I-797 H1b while I was in India year 2008. 2. Got a job offer from some new company will get client letter (stating roles and responsibilities and location of work). Filling COS from H4 to H1B what are the chances I can get consular processing instead of COS?
My evaluation is that you will get a COS because your I-94 has not expired and you remained in status up to the time the fee receipt was issued. If your I-94 had expired that increases your probability for consular processing.
3. If I don't get a client letter or I am getting better offers from direct/big companies that can also provide client letter and also getting offers from clients itself. How much time do I have for COS as my last salary slip on L1B was on AUG-12-2013 and now the GAP between last salary slip and filing for change of status is growing?
Since you had filed for the COS before your I-94 expired you have not gone out of status.
What USCIS will do is to wait until there is a decision on your H4 COS before approving your new COS to H1B.
4. As far I know I am cap exempt for 6 years these 6 years will complete on October 2014.If there is more Gap in finding the job will there be issue like COS not approved or 2008 H1B not accepted/invalidated because of salary slip GAP or H1B visa not used for 5 years.
No see #3
5. There are few companies that can file my change of status based on their internal project. What are the chances getting COS approved on internal project? Are the chances same as filing with Client offer and letter?
USCIS always scrutinizes jobs where you work for an end client more than when you are going to be employed directly by the petitioner. The issue is control. Who has the right to direct and control the work product of the employee.