As you may already know, a new bag is coming in Patch 5.1 that will hold all of the various items associated with Cooking. Today I popped over to the PTR to check it out!
The bag is currently being sold by Nam Ironpaw, the token vendor at Halfhill. He'll give you a Portable Fridge for 10 Ironpaw tokens. This bag Binds when Picked Up, so you can't buy extra ones for your alts. Since Cooking can be started by level 85 toons, you can easily take those toons out there to get their own bag. The bags are not unique, so you could theoretically purchase several on one toon. I'm not sure that's a practical thing to do, but that may depend on how you have your alts set up.
Here's a pic of the vendor page with the new bag:
Something to keep in mind is that there are tentative plans to create a Void Storage-esque option for Cooking. If this is implemented, it could reduce the need for massive bag storage. It's up to you to decide how invested to get with the bags vs. waiting for a better storage option.
I'm excited to see this new bag, currently I use the mail system as my pantry :) I'm not sure which toon will get the bag just yet, but hopefully I'll have that figured out by the time 5.1 drops. I have to say I'm pretty tickled to see this item get implemented. We asked for this in Beta and while it would have been nice to have it for launch, I'm glad to see them work it into the first big patch for MoP. Thanks guys!
If you have any other questions regarding profession content on the PTR, leave a Comment and I'll look into it!