Okay, so here's the story:
It looks like regular seeds are also partly dependent on some ID that is unique to each DS. As far as we know, this ID can't be retrieved by anything except an AR (and so far Kaphotics hasn't been successful in making a code for that).
However, since this ID is only one 32-bit value, it's feasible to brute-force every possible combination and find this ID, so long as you know the seed for a particular time\date\MAC address. (I wrote a program for determining this seed a few pages back, but I've found it's a little buggy and won't be fixing it until I integrate it into RNG Reporter.) It's a process that will take hours, maybe even a day or two to complete, but once you have that ID you can predict IVs (and more importantly nature\ability\shininess, which C-Gear seeds can't do) for any date\time, for that DS.
This is going to be a pretty complex process, so I'll make sure RNG Reporter 9.0 will guide the user through it, step by step. But I'm swamped this week, so don't expect to see progress on it until the end of next week. In the meantime, I'll see if I can find time to get RNG Reporter 8.4 out in the next day or two. I won't be posting any guides for it, though - I expect the people who have been beta testing it to help. :)
Originally Posted by Fat Kaphotics
It's screwy every 4 years
You mean like this?