Maybe I'm being picky, but I'm kinda scared of Emms' suggestion of 7.cd ed 8.a3 cd 9.ab dc 10.b5 Ne5 11.Bc2!? with a strong initiative for the pawn...also doesn't your line after 7.a3 lead to the same sort of IQP as often occurs after 6...cd 7.ed d5?
Rubinstein Nimzo Question

I doubt it since you can't force White to grab on d4 with a piece. I think d5 and c5 always leads to an IQP in the Nimzo or that pawn triangle unless White avoids it. The only thing I can think of is 6.Nge2 d6.
If you play c5 and d5 I think the least White can do is just sit there and either wait for you to swap or find an advantageous time to capture on d4.

I doubt it since you can't force White to grab on d4 with a piece. I think d5 and c5 always leads to an IQP in the Nimzo or that pawn triangle unless White avoids it.
Yeah that's kinda what I thought, I was just sort of checking
The only thing I can think of is 6.Nge2 d6.
I have two issues with 6...d6, first I don't think it's objectively so great after 7.0-0 0-0 8.a3 Ba5 (8...Bxc3 9.Nxc3! and taking twice on d4 is met by Bxh7+) 9.Qc2 etc. and secondly 7.a3!? Bxc3 8.bc is transposing directly to a Samisch line outside of my repertoire.
If you play c5 and d5 I think the least White can do is just sit there and either wait for you to swap or find an advantageous time to capture on d4.
So if I want to play the Hubner Wall (1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.e3 c5 5.Bd3 Nc6 6.Nf3 Bxc3+!) with Black, is there any way to avoid the IQP which results from the 6.Nge2 main line,(and which I'd ideally rather not play from the Black side) specifically 6...cd 7.ed d5 8.cd Nxd5?