Take a look at this thread in the
Trusted Travelers forum:
Two laptops in one bag at PreCheck
I recently went through Pre at LAS with 3 laptops, 2 tablets, a kindle, 2 phones, a Mifi and a variety of accessories. The TSA agent told me that folks like me were called 'Best Buys'. We had a good laugh as the agent looked (quickly) through my bag, and I was on my way. Much quicker than having to dump everything!