No idea about that, but I don't see the need for one - I think there's already way too much hair-splitting about the minor discrepancies between extremely similar versions of D&D.
Not specifically, but it would seem the the forums at Goblinoid Games would fit the bill.
Yep, Goblinoid Games forum is the place, being mainly focused on Labyrinth Lord - thus Moldvay. Here's the new forum just started a few days ago: http://www.goblinoidgames.com/forums/index.php ...and here's the old one: http://www.freeyabb.com/goblinoidgames/index.phpThey should do the trick.
The Save Or Die podcasters might be able to help too.http://saveordie.info/
Dragonsfoot has a forum for BECMI and B/X. Their forums cover all editions bar 3 and 4.
Yeah one could say DF is even heavier on what they call Classic D&D (B/X and BECMI) than AD&D traffic-wise. I would definitely think of it as the go-to place for those editions.
Definitely the Dragonsfoot Classic D&D forum - focuses mainly on BECMI and B/X moreso than Holmes, however. Goblinoid Games and LL would then be my second choice.
here you go: http://www.dragonsfoot.org/forums/viewforum.php?f=15&sid=53da3282998a65de0a535d9cff6e1175