Crutchfield has the RTi4 and RTi6 bookshelf speakers in stock. The center channel CSi5 is expected on October 15. No word on the tower speakers.
I went in a local Circuit City yesterday evening and asked when the store was expecting their new RTis. The guy I usually deal with there said they've been given no estimated delivery time yet from their headquarters. Even most of their display models from the old RTi line are gone now.