Followed advice of others.
Used 800-421-4655. While waiting for a live rep the recording on the line said if you "want a new mp visa call such-n-such phone number and you can get 30,000 bonus miles!"
I waited for my live rep and told her I was calling about a new MP chase visa card offer; she promptly said "Oh, the one with 50,000 miles?" Good sign.
Transferred to the visa folks. That agent also promptly said they had a 50,000 mile offer that was good upon your first purchase "no matter the amount of the purchase." She went on about how you could use those 50,000 miles for two domestic saver awards!! Oh WOW
She said that at the beginning and the end, but I guess she was just making a point at how great 50,000 miles are.
Took my application info, read the long T&C, gave me immediate approval, it may take 8 weeks for miles to post after purchase.
50,000 was mentioned a few times, similar to what others have noted.
I have an old, but active, MP visa. Didn't seem to be an issue. We'll see about miles.