I am currently living in India and I've NEVER worked/living in US. Here is my case summary :
Employer A filed an H1B petition for me in 2012 which got approved recently. I also interviewed with another Employer B who is willing to get H1B for me in 2013.

1) If I do not get an H1B stamped and then work based on approved petition by Employer A, then what happens to it? Will it automatically get cancelled after some time? Can i get H1B stamped (and then travel) based on it after a few months (say 6-8 months) if I do not have any other option?

2) Can Employer B file a H1B cap-exempt petition for me in 2013 based on the fact that I have a cap-subject approved petition in 2012? Note that I have never held employment based on cap-subject petition.

Would be great if someone can answer these questions.

Thanks a lot in advance,