Earlier today I found that the timer for the delay (with the C-Gear seed, of course) is located at 023FFC3C (White). By fixing it to a constant number, I was able to get the same consistent results.
According to the Japanese blog referenced earlier, this is how that seed is calculated:
0xABCDEFGH + last 3 bytes of the DS MAC address
where AB = month * day + minute + second
where CD = hour, in 24 hour format
and EFGH = year + delay
It's basically the same as last gen, except for the MAC address part. Unfortunately, things aren't that simple.
Last 3 bytes of MAC Address - 00:00:00
October 17, 2010, 18:00:30, delay 0 to 2
August 27, 2009, 18:00:38, delay 1 to 3
both dates give the same results, confirming the above formula
Calculated Seed IV MTRNG Result
Apparently it's doing something to the initial seed, and the result becomes the new seed for the IV MTRNG. Once we figure out exactly what it's doing with that, we can start RNGing for wild Pokemon IVs on a cartridge.
Also, the procedure would be mostly the same as last gen, except instead of selecting Continue, people will have to turn on their C-Gear at the right moment in-game (not just after selecting Continue, that does not reseed the IV MTRNG).