The buzz I'm hearing most is that you'd do best getting the 50mm Alpha lens that goes to f1.4, achieving a 75mm view at a 35mm sensor equivalent but sacrificing auto-focus and image stabilization.
It's true that if you buy the $200 LA-EA1 you will be able to connect Alpha A-mount lenses to the E-mount NEX-VG10, so it's definitely a possibility. BUT, as Paul notes, you lose auto-focus and image stabilization. The LA-EA1 lets the camera body talk to the aperture ring of the lens, but you don't get image stabilization because, as an article at Alphatracks explains about the NEX-5/3 cameras:
Sony Alpha dSLRs are famous for having image stabilization built into the body. In order to make the NEX bodies as small as possible, however, Sony engineered the small cameras to use in-lens stabilization. As a result, A-mount lenses mounted to the NEX series cameras will not have stabilization.So I'm assuming the NEX-VG10 has the same problem...[unfortunately I couldn't confirm this]
And if I lose the auto-focus and image stabilization, well I already have a camera that does shallow depth of field and has annoying limitations: the Canon 7D!
Alphatracks.com: A-Mount lenses on the Sony NEX series
Amazon.com: Sony LA-EA1 - Lens adapter Minolta A-type - Sony E-mount
B&H: Sony NEX-VG10 Interchangeable Lens Handycam