Finally a GPU bracket for AIO, from NZXT and with a good price, 30$. The final result is pretty similar to Accelero Hybrid, but the VRM's fan is bigger and maybe also better. The cool story is that is compatible with a lot of AIO and not only "NZXT".
Compatibility:
Nvidia: GTX 780, 770, 760, Titan, 680, 670, 660Ti, 580, 570, 560Ti, 560, 560SE
AMD: R9 290X, 290, 280X, 280, 270X, 270 HD7970, 7950, 7870, 7850, 6970, 6950, 6870, 6850, 6790, 6770, 5870, 5850, 5830
The compatibility list is based on AMD Radeon and NVIDIA's reference board layout only. Please check the height restriction before purchase.
Compatibility:
NZXT: Kraken X60, Kraken X40
Corsair: H110, H90 , H55 , H50
Antec: KUHLER H2O 920V4, KUHLER H2O 620V4, KUHLER H2O 920, KUHLER H2O 620
Thermaltake: Water 3.0 Extreme, Water 3.0 Pro, Water 3.0 Performer Water 2.0 Extreme, Water 2.0 Pro, Water 3.0 Performer
Zalman: LQ-320, LQ-315, LQ-310
Official site