There will be a Swap Table room for sure with some gear and LPs. I'll have a couple boxes of used LPs, CDs and a couple pieces of gear and I'm not sure what the others are bringing.
As to new stuff, in past years there were vendors with accessories and vinyl, but I'm not quite sure what this year will bring. Madisound will be there so they may have some accessories and drivers/caps and other DIY type stuff, but that's just a guess on my part. The dealers would probably love to sell you some of the new gear they're demoing too.
Also, I'm sure once folks start talking about gear there will be some swapping and deals going on too. At any rate, you'll have a great time. Be sure to bring something you like to listen to and you'll be able to use it as a reference on many of the systems there.