I just purchased a new pair of Descent bib shorts with a molded chamois - lots of air holes and no seams!
Very comfortable. I used to be ummm, rather largeish too. But now that I can use my aerobars without suffocating, I still find that I'm too used to good padding to go back. These bibs do the trick and are forgiving around the midsection when the gut comes out to say hello!