You can have as many H-1Bs as

you want. But GC only can base on one full time H1B. Theoretically you can apply part time HIB. But how the company convince Imm would be a problem.

Also, H1B for full time job with the wage certanty is not changeable. You don't get any bad credit for H1b fools but company. However, when you apply for Visa (not status), you have to report every single H1B you hold. By that time, you could be in Hot Water.