We did toy with this idea at FormFonts; but in the end we rejected it. We even went as far as to write some custom scripts to produce thumbspins (as we called them). One script physically rotated the model, rather than orbiting it...so you didn't have to pass through the shadow side. Another script panned around a central point, for large area models.
The thing to realise is that it's not a one-size-fits-all solution. It's great for certain models (upright or fairly compact) but not suitable for a great many others.
For instance, we get many requests to model sofas. Not only are sofas generally even longer than the garden bench example of Al's...so you lose even more of the ends, or zoom out so far you can't see anything...but they are only remotely interesting in a 90* cone of visibility around the front. The other 270* is as boring as hell...especially right around the back. Trucks, buses and lengthy wall units etc fall into the same category. The vehicles are OK all around, but the ends spin past like the business end of a centrifuge.