This is a bit surprising but it looks like Samsung doesn’t want to mix up the Omnia range with two different OSes. To avoid any confusion related to the Windows Mobile powered Omnia phones, they have dropped the OmniaHD name from its Symbian powered OmniaHD i8910. The phone will only have the model number and will bear the same features as before.

A wild speculation but is Samsung prepping a Windows Mobile powered OmniaHD in the near future?

To avoid confusion between the original Omnia, which is Windows Mobile, and OmniaHD, which is Symbian, Samsung is deferring to the model number.

Source