It certainly is possible, but since that portion of the private key space has so much attention and no collision has been found, I would choose a different starting point.

BTW, the math suggests that finding a collision by testing a sequence of private keys is impractical. It might seem like the odds of finding a collision are good because there perhaps 2^256-160, or 79,228,162,514,264,337,593,543,950,336 private keys with that RIPEMD-160 hash. But, the probability of a number colliding is still extraordinarily small. On average, you still have to try 2¹⁶⁰, or 1,461,501,637,330,902,918,203,684,832,716,283,019,655,932,542,976, numbers before finding a collision.