I am wondering if the player who mention he found four white stuffies, found them all on the same shard he plays on. Or was this a situation where they were found on various shards where he might have 6 players on each shard and thus a much larger base of stuffies to have a chance at the white ones.
Keep in mind that if it's the second one then that's still alot of picks to get those 4 white ones. Plus if your comparing this against the average account, that a number of players only have characters on the shards they actually play on. Thus using the figure of thier being 75,000 accounts and the possiblity of 24,000 white stuffed animals might be a tad off.
I believe its quite possible that the UO staff may have read our posts here that we wanted some really scarce gifts in the future. Thus creating interest in them and making some players feel like they won the lottery this time around if they obtain one.
To get a real idea of the ratio of how many white stuffed animals were given out, imo you would need a much larger data base to draw from to come up with more difinitive answer.