Muse about what it might be all you wish, but you know what the facts are, and it's pretty damn nigh impossible to avoid facts. It wasn't the CPU speed for the reasons stated earlier, and frankly it appears your refusal to accept this has conditioned your thinking to the point of no return. Whether you wish to accept it or not, it also isn't a feature within custom firmwares, which are changed negligibly over their official counterparts.
The current "hacks" have people editing attribute files within the Pulse game itself; their flying Feisars have absolutely nothing to do with custom firmware itself aside from it facilitating the use of the hacks because UMDs can't be pressed at will (said hacks would work on official firmwares too if this could be done). The person you speak of may have conceivably had one his own Pure ship attribute files modified, but I'm not aware of any such hacks circulating the Internet. This isn't to say such hacks don't exist for Pure; it's only that I'm pretty dialled into the PSP news scene, and I likely would have heard by now.
Having said this, there is one overriding solution, and that would be to encrypt the plaintext attribute files within the game such that bored teenagers don't go digging and modifying things to win friends and influence people.
- F