X-bit Labs says owners of AGP systems shouldn't expect any more new graphics cards from NVIDIA:
At the same time, we haven’t seen any Nvidia GeForce 8XXX based graphics cards designed for AGP 8x interface. It turned out that the problem lies with the latest AGP-PCI BR02 (HIS) bridge revision that cannot work with the new graphics chips. It was supposed before that Nvidia will still release a new A05 revision of their BR02 bridge that will be compatible with contemporary GPUs, thus giving their partners the opportunity to refresh the lineup for the AGP interface. However we learned now, that Nvidia gave up this idea.
So, we will see no new graphics cards from Nvidia with AGP 8x interface. Nvidia explained their decision by absence of sufficient demand for solutions like that.