No official specs for the device has been released, we should here more about it this week when Nokia unveils both this and its CDMA version of the Lumia 800.
This Lumia 719 has a long physical button with the "back" "start"and "search" buttons (just like on the Lumia 710). It also has a 3.7inch screen and the shape almost resembles that of the Lumia 610. So it will be in the low range of Lumia phones (with 710 and 610). and it looks like it will only be available in the Asian Market just like the Nokia 801T.
Here's a comparison of the Lumia 719, with the 710 and 610: