It does look a lot like a Benonigrad reversed, the big difference being that 1.d4 c5 2.d5 f5 is a move order that gives black what he wants - a modern benoni centre.

1.f4 d5 2.c4 d4?! feels like a mistake, black should be opening the centre instead of closing it. Compared with 1.d4 f5 2.Nc3 c5? white does have an important tempo extra so 2...Nc6 may not work due to 3.cxd5 (I haven't checked though...) but white's play feels a bit dreary to me after 2...c6 or 2...e6.

Maybe one could trick around with the move orders, e.g 1.f4 d5 2.g3 c5 3.c4 when d4 seems more logical - but black has lots of alternatives to 2...c5, unfortunately.

Anyway, this acc benonigrad seems to have a few supporters here and there all over the world, there's a guy in Helsingborg who's been playing it for many years, though strangely enough I couldn't find any of his games in my database.

The stem game seems to be Laroche - De Riviere,J Paris m2 Paris, 1856 1-0, and the latest are 4 games by Golovankov, a russian 2300 player who used it last year to score 4 of 4 against 2000-2100s, so maybe it's a good idea when playing 'must win' games?!

I'm a long time bird player. In the past I experimented around with 1.f4 d5 2.c4!? a couple times in tournaments and got fair results as I remember, but this was against very weak competition. ECO calls this the mujannah (flank) opening.
Recently in my urge for original positions I've re-examined it and I've gotten some pretty crazy positions. Maybe someone here will like it or could suggest some improvements.

1.f4 d5 2.c4!?
2...dxc4 I don't think is very critical, white can go with a soon qa4+ and get the pawn back or develop and play in true gambit style. in blitz games ive played as white on icc sometimes i get a big pawn center, othertimes d4 square becomes too weak and position is just bad. but either way the positions here are more familiar so I really am not interested in these lines.

2...d4 is interesting. I like playing 3.Nf3 and if Black plays 3...c5 white can go in for a bizzare benko with b4. I haven't really investigated this line much, but from what I've got it just seems about playable for white. heres one line
1.f4 d5 2.c4 d4 3.nf3 c5 4.b4!? cxb4 5.a3 (black can try to win another pawn with Qc7!?, but it gives away center pawn to nxd4, and after Qxc4, e3 seems to hold game in balance, while after Qxf4, e3 once again gives white some play after q move and xb4. this has much room for original analysis.

another interesting line is 1.f4 d5 2.c4 nf6 3.cxd4 nxd4 4.e4 !?(?!) Nxf4 5.d4 Ng6... this is called the sturm gambit. I went over sturm's games as he played white and he won most of them, but its probably dubious with proper defence. anyway, a safer alternative is just 4. Nf3 (if nxf4 qa5+ winning knight is cool trick), nc6 and now 5.d4 looks ok, or just g3, if 6...bg5 7.Qb3, and if g6 then nc3 seems fine.

but the very interesting lines run after black plays the conservative 2...e6 or 2...c6 (as usually happens since black is usually clueless after 1.f4 anyway let alone 2.c4) and here comes in what I call the whale variation for white:

1.f4 d5 2.c4 c6 3.nf3 nf6 (immediate d4 is possible but nf6 prevents ne4), 4.Qa4!? (or Qb3, I haven't decided which is stronger yet), 4...d5 5.Ne1!? (the point, queen move frees the e1 square for the knight, given the chance the knight likes to hop to f2-e3, where it blockades the d3 weakness, protects f4, protects critical e5 square and gives chances for even a white b4!? possibility eventually.
here are some lines:

1.f4 d5 2.c4 c6 3.nc3 nf6 4.qa4 d4 5.ne1 d6 6.nf2 bd6 7.ne3 bd7 8.Qb3 c5 9.nf3 nc6 10.g3 (all the while b7 pawn is under attack) qc7 11. bg2 e5? 12.fxe5 nxe5 12.nfxe5 bxn 13.Qxb7 and white is good.

and 1.f4 d5 2.c4 e6 3.nf3 nf6 4.qa4+ bd7 5.qc2 (nb4 Qb1) d4 6.ne1 nc6 7.nf2 bd6 8.ne3 (the point of qc2, threatening c5! now if e5) g6 9.nf3 qe7 10.g3 and if e5 trying to push white off the board then fxe5, bxe5 bg2(otherwise c5 followed by nf3++ if immediate nxd4) rd8 nexb nxn nxd4 wins the pawn.

anyway, all of these moves lead to very interesting positions with the white pieces on f4, c4, nf3,ne3 for an original game. that is the whale setup; f4,g3,nf3 is the triangle tail on a whale, while c4 is the waterspout gushing upwards. a stretch, but does the dragon really look like a dragon?

Let me finish by showing a cool game I won against a strong class A player a couple weeks ago with this variation:

1.f4 d5 2.c4 e6 3.nc3 nf6 4.qa4+ bd7 5.qb3 d4 6.nd1 bd6 7.nf3 c5 8.g3 nc6 9.bg2 qb6 10.qc2 a5 11.nf2 nb4 12.qb1 qa6 13.ne5! bc6 14.nxb nxn 15.b3? (gives black some play, e3 is worth a go maybe) a4 16.bxa4 0-0 17.0-0 rfb8 18.d3 qxa4 19.bd2 (covers all holes) h5 20.ne4 nxn 21.bxn f5 22.bf3 g6 23.qb2 e5? (gives white too much play) 24.fxe5 bxe5 25.rfb1 bd6 26.qb5 qxq? (nb4 maybe better) 27.rxq ra6 (terrible but there not much better, white has too much pressure on b file and bishop is a monster) 28.bf4 bxb 29.gxb nb4 30.bxb7 rxb (black is lost no matter) 31.rxr... and white went on to win.

so definitly this could have some potential, especially for those seeking original and creative positions and possibilities. please share your thoughts