If I understand correctly (and I've been looking at quest in respect of another project) that questviewer is only a very basic part of the programme. Much programming needs to be added to turn quest objects from 3d models to ships.
This is the reason, I understand, why the SDK plans were shelved. If it were that easy vstep would have said "no SDK, but you can use the quest SDK instead..."
EDIT: I must point out that is not a comment from the developers, its only my guess of what they will say.
Stu