According to a literal reading of D&C 77, shouldn't the seventh seal have been opened around 2000 (give or take 5 years, depending on when you date the birth of jesus)?

I'm declaring it a non-event, that is if such a declaration has not already been made.

But, the Mormon church was founded in 1830 and the D&C states:

"THE rise of the Church of Christ in these last days, being one thousand eight hundred and thirty years since the coming of our Lord and Savior Jesus Christ in the flesh...." (Doctrine and Covenants | Section 20:1)

So, according to the church, Jesus was born in the year 0 (or, actually 1 B.C., since there was no year 0). You can put together an approximate/unofficial L.D.S. chronology from that bit of information, and I think your estimate is about right.

How do you know it hasn't been opened?

If opening seals it the same as turning a page on a calendar, then it doesn't really mean anything does it?

I think the whole idea of the seven seals, and the year 2000 have gotten alot of people into a slow motion, don't realize it, sense of cog-dis. Jesus isn't coming back. The longer and deeper we go into this century and no Jesus, more and more people are going to slowly realize that nothing is happening,nor is it going to happen.

Some people think this line of reasoning is "too simple", but I think Christianity has painted themselves into a corner. It will become like the religions that worshipped Zeus or Apollo in less than 1-2 hundred years.