I have a small AVR project in development that can generate a rock-steady 400x256 bit-mapped monochrome composite video graphic display using one 74ls00.
It works on any MegaAVR with >=32K external ram. It even has enough ops left over for features or even useful work.
This system currently produces a text resolution of 40x32 characters in 10x8 cells for fastest rendering given the frame buffer layout (not linear). It could easily do better depending on need.
Has anybody achieved better video resolution on the AVR without the use of special/expensive chips? What other AVR composite video generator projects are out there people know of?