Net Warrior wrote on 12/31/09 at 15:06:30:
Then I was looking at the old main line and found 4.Nf3 Bg4 5.Be2 Nc6!? in a book from the '90's. The author only gave it sparse coverage but the more I looked at it the more I thought it was playable. I analysed what I figured would be the 3 main continuations with Fritz 10 and and black was close to equalizing in all three 6. c4, 6. ed, and 6. e6. It was particularly nice to have the Bishop out in front in the 6. e6 line. I think there is room for some original play in these lines. Oh, and keep in mind that I'm only a USCF "A" player so none of this is solid gold.
I looked into this, and it turns out your judgment of this line is pretty good. It was played on many occasions by the strong Estonian GM Vladas Mikenas. I have four of his games with it in my database, and Bagirov mentions others in his 1973 book.
The first thing to understand is that after 6.0-0 the only line of independent significance is 6...Nb6!?, since leaving the knight on d5 permits White to transpose into a version of the Old Main Line where Black's knight appears early on d6. This is considered disadvantageous, because White will play exd6 followed by d5. So 6...Nb6, which is the way Mikenas played it, and now there are two challenging moves.
7.h3 Bxf3 (not 7...Bh5 8.e6) 8.Bxf3 exd5 (8...e6 doesn't work out well) 9.exd5 Qxd1 10.Rxd1 e6 and sooner or later White will exchange on c6, debilitating Black's queenside pawns. Mikenas must have felt that Black could hold the game, however, since he went for this repeatedly. In the last game in my data base, he is defeated in this line in 1979 with Kengis, of all people, in command of the white pieces.
7.a4 is a very big challenge. The main point is that 7...dxe5 8.a5 e4 9.Ng5 is very good for White. Black must try either 7...a5 or 8...Nd7!? 9.a6 b6. Here Bagirov, aped by both Eales and Hort, gives 10.dxe5 Ndxe5 11.Nxe5 Qxd1 12.Bxd1 Nxe5 13.Bxg4 Nxg4 14.Bf4 as favorable for White. This is utter crap, since Black is a pawn up and perfectly safe after 14...e5. But White also has 10.h3 and 10.c3. 10.h3 Bxf3 11.Bxf3 Nxd4 12.Bxa8 Qxa8 looks about equal to me. But 10.c3! is a challenge and I will let others now have their say about it.