H1B to F-1 and to H1B on graduation

1. I had an H1 filed in 2000 by a company in US and I worked with them for 5 mnths before being laid off. I went and joined a MS course in 08/2000 and got my H1 cancelled and new F1 issued.I had an OPT issued during my MS in 2002. However, I left the next day I graduated in 12/2002.So essentially i did not use my OPT though it was issued.
I came to Us again in 2005 and my first cycle expired in 06/2008 and extended to 2011. I am going to B-school in 08/2008 and I believe that I am not eligible for another OPT since already used one during masters?

2. Have H1b- cycle 1 expired in June 2008, extended to May 2011. Now, I am planning on changing my status to F1 and continue education in an accelerated MBA course. Since I will not have OPT eligibility after graduation, can I ask my potential employer to request a change in status to H1 without reapplying for a new H1 through the cap/lottery? Would this mean that I fall outside the preview of lottery and cap and use the remaining time on my current H1(cycle 2)??

3. If i need to travel internationally as part of course work, I understand that i need to get a new visa stamping in the country that I am travelling to. Does that mean that my H1 b visa on passport will be invalidated without prejudice and I cannot use my cycle 2 H1B visa(mentioned above)? Will I have to get a new H1B petition filed on graduation and go through the lottery?

You may not ask your potential employer anything. There are too many native U.S. workers who need that job.

You are required to leave the country immediately after your studies and find a job in your own country.