Actually the lens for the Holga 135 Panoramic camera does come off. It's the first Holga camera to have this capability. The reason is because the camera comes with two detachable lenses...one standard, and one pinhole.
I'm curious to see if this is gonna be a one-off, or if Holga is going to include detachable lenses for other models in the future.
The Holga catalogue (PDF available from Tokina at http://www.tokina.com.hk/) shows the 135 Pan as the only camera they have currently, with removable lenses, is 1.3 (panorama) and recommends the use of ASA 400 film.