The rumors I've been hearing is the boxset should be out sooner than the next film. They are already working on it.
This wasn't the exact article I saw but someone asked for it on the WB FB page for xmas, and they responded like "very likely if you are a good boy" with a wink or something. I'm paraphrasing but I wouldn't be surprised if the boxset is announced THIS year.
Here it is on blu-ray.com's Friday forum - post # 798
Another person on WBShop's Facebook said all he wants for Christmas is 'Friday the 13th 1-8 on Blu-ray'.
They responded with 'You may get that and more if you are good.'
Hopefully the '...and more' means 'Jason Goes To Hell' and 'Jason X'?!