GISJoel, from the Voyager Forum, has taken pictures of the enV and Voyager side by side to come up with estimated size and dimensions of the LG Voyager. He took the known dimensions of the enV and scaled these to the Voyager. Here is his work:

Length: 4.725″
Width: 2.1375″
Depth: 0.75″

Credit for images and dimension calculation goes to: