Now i haven't a board or fritz here, but the ...h5 plan looks mildly suspicious when White hasn't touched (weakened) his kingside pawns like say in the Bd3/h3 or g3 setups. Okay if 10. f4 doesn't work, then White could go 10. Nd3 first and then decide between f4 and/or a3 and b4. Normal classical KID play really. Better player wins, but White  has a slight theoretical plus i suspect.

Hello, there is another plan with 

1.d4 Nf6 2.c4 c5 3.d5 e5 4.Nc3 d6 5.e4 Be7 6. Be2 Nbd7 7. Nf3 followed by 0-0 and Ne1 and f2-f4. This was covered by Marin in recent CBM, he concludes Black has some problems to solve, if i recall correctly. 

Looks like a simple plan for White to try.

NIC Yearbook 80 has a good article about the Czech Benoni:

There are 2 plans for white:

1 - The positional system
lines with g3

2- The aggressive plan
lines with Bd3-Nf3-h3

Conclusions in Yearbook 80:
Black's position is solid and hard to break down....The variation also avoids early simplification, which makes it a useful weapon for the stronger player.

All black games feature D.L. Nisipeanu, who is certainly the top guy to follow...

I am not sure I am convinced by the idea g2-g3-g4, I think the pawn may want to stay on g3, while maybe the h4-pawn wanted to be on h4 (to prevent Nf6-h7(-g5 or Bg5), which I assume is what black intended in the game with the move 16...Nh7). Of course if one chooses that set-up then Bf1-d3 is probably not so sensible - on e2 it would be potentially better placed, or it could even go to h3 to swap itself off (maybe risky with the weakened white squares on the kingside?!

Looking through the databases, I thought that in the following game white did a lot of very logical things:

Wendt,R (2290) - Lang,S (2250) [A56]
BL2-O 9495 Germany, 1995

1.d4 Nf6 2.c4 c5 3.d5 e5 4.Nc3 d6 5.e4 Be7 6.h3 Nbd7 7.Nf3 Nf8 8.a3 Ng6 9.b4 b6 10.g3 Bd7 11.h4 h5 12.Be2 Rc8 13.b5 a6 14.a4 Ra8 15.Bd2 Ra7 16.Nh2 Nf8 17.Nf1 g6 18.Ne3 N8h7 

However now I am not so sure what white should do next, does his king really want to stay in the centre?! But if not, where would it be safe?! On the other hand if white doesn't play on the queenside, then black would, so the queenside is not so safe and white's attacking potential on the kingside is reduced through his own g3/h4 set-up... The decision to castle queenside in the game looks very dangerous to me.

19.Qc2 0-0 20.0-0-0 Qc7 21.Kb2 Rfa8 22.Ra1 Qc8 23.f3 Be8 24.f4 exf4 25.gxf4 Nd7 26.Rag1 Kh8 27.e5 dxe5 28.f5 Bf6 29.Qe4 axb5 30.axb5 Bg7 31.Ra1 Nhf6 32.Qc2 Qb8 33.Rxa7 Qxa7 34.Qb3 e4 35.fxg6 fxg6 36.Ng2 e3 37.Nxe3 Ne4 38.Kc2 Nxd2 39.Kxd2 Qc7 40.Qc2 Ra3 41.Ncd1 Qf4 0-1

Anyway, this opening is a bit of a dilemma for white sometimes.

Interestingly for once Cox (Starting out 1.d4!) and Palliser (Play 1.d4!) recommend the same system! Normally Cox has something sharper in his recommended repetoire than Palliser...

I note however that both just assume black will castle, Cox: 1.d4 Nf6 2.c4 c5 2.d5 e5 3.Nc3 d6 5.e4 Be7 6.h3 0-0 and with more or less the same move order Palliser: 1.d4 c5 2.d5 Nf6 3.c4 e5 4.Nc3 d6 5.e4 Le7 6.h3 0-0.

But what about 6...Nbd7 7.Nf3 Nf8? The typical plan for black here would be Nd7-f8-g6 followed by h7-h5(-h4 if possible and then Nf6-h5-f4 - which is why g2-g3 is played a lot at some point in this variation and also h3-h4, too). Alternatively there's always the diea h7-h6 + Nf6-h7-g5. Generally, doesn't 6...0-0 simply often seem like black is rolling over and dying??! With that Nf8 idea black at least has something to do while trying to figure out where his king should be going (or whether it should just remain in the middle).

yes, that's right
the more and more I look into this book the more I like it

Yes I meant Starting Out: 1. d4! by Cox, I just messed up the title.  I am pretty sure he recommends this line somewhere in the chapter on the modern benoni end benko, but since I am at work and dont have the book with me I have to check it out tonight. I believe the Ivanchuk-Seirawan game is given there somewhere to.

o.k., you are right, 
czech benoni is 
1.d4 Nf6
2.c4 c5
3.d5 e5

so white is comitted to c4 in the czech benoni.