It is based on the smaller Landcruiser, with the LX based on the bigger Amazon Landcruiser. Rebadged in the same way that an RX is a rebadged Harrier, the specification is higher on the Lexus.
The GX, LX 4x4s and the ES saloon aren't available in Europe, and probably not Japan, so the only possibility of finding one over here is a US import - I'm not aware of any on these forums.