I'm a member of a spanish board (elotrolado.net), and we think we discovered something.
One user tried to install flashme on his DS, and it got recognized as DS Lite. He continued the process and now he has the Lite firmware, and he have four brightness levels.
The problem is that not all DS get recognized as Lite (only v5), so we are asking for help on how to sign the lite firmware as the old one, to be able to flash all old DS with it, so we can get the four brightness levels.
I'm trying to contact loopy, but I can't find his e-mail, so If any of you can talk to him about this please do it.