I've seen Vallejo acrylic thinners in large bottles at local art stores. Are they the same as smaller size Vallejo thinners sold at hobby shops?

I would think so. Vallejo also sells larger tubs/bottles of their mediums and pastes.

Yes, they're the same. Vallejo has a much more extensive paint line than just what they make for us modelers. And you probably haven't seen HALF the products they make for modelers! Check out their website at http://www.acrylicosvallejo.com/en_US
and prepare to be amazed.

If it's cheaper at the artist supply go for it .

Wow! they've been around since 1965. And to think I imagined them as just a small specialty model paint company.
Thanks for the link.

Was it the milkly white stuff or the clear? I know I have the bigger bottles of the clear thinner that was designed to thin out the Model Color line and it works great.

I don't remember the color. I have a bottle of Vallejo thinner bought from a modeling store, and I do remember I was amazed at the big size of the bottle at a local art store.

Anyway, what exactly is the Vallejo thinner? Is it distilled water plus a few other ingredients?