The place I got my bricks actually produces them... in Germany, but thats closer than China or the states anyway. They're not the cheapest around, but they are exactly what you're looking for - might be worthwhile if you go for the weekend trip version...
Kandern Feuerfest GmbH
The homepage isn't all that informative, but if you're interested I can give you more info and/or translation services.
But check out Inishtas idea first, sounds like like a good advice.