Why big and not great? Specially in context with rich big doesn't sound right. It sounds a bit like saying "We are obese and rich".
That was a pretty confusing sentence to me as I have problems figuring where and when this could be said in English... I mean, I get sentences like "We are big in Japan", but that's still confusing.
I'm told by a native Indonesian speaker that this is an odd sentence and not natural or likely to ever be used like that