Using the benchmarks from here: https://www.servethehome.com/monero-mining-benchmarks-select-dual-intel-xeon-e5-systems/ we can figure that something like a Xeon E5-26870 V1 (available since March 2012) can do about 375h/s. As you can see in the image below, the Bytecoin hash rate averaged at like 1500h/s for the duration of its fake existence (about 20 months).



So basically if they had 8x of those CPUs they could've generated it in 10 months. And if they had 80x of them they could have done it in a month. Given the AWS cost at the beginning of 2014 it wouldn't have been insanely expensive to just use AWS for it; if I had to hazard a guess I'd say $20k or less in AWS cost.