For the west coast, what about San Diego?
The convention center has over 525,000 gross square feet of contiguous exhibit space on the ground floor alone.
Sure, you'd have to work around ComicCon in July, but that shouldn't be a problem.
It's also on the bay, with Seaport Village and Petco Park (amont many other things) within walking distance.
And you won't have to worry about the weather!
Steve