The 8003 does not have a color space converter between the VSP and TTL pixel port output. Therefore the only way for the 8003 to drive a RGB LCD is possibly by-passing the VSP completely. Of course this defeats the purpose of having a VSP in the path.
The new ADV8005 is basically the same as the 8003 except for a few fixes / enhancements and it added a CSC in front of the TTL pixel port output to drive LCD panels directly.
http://www.analog.com/en/audiovideo-products/analoghdmidvi-interfaces/adv8005/products/product.html