Richard,

Having a Makita and a Prazi in my toolkit, I would choose the Prazi. But only if the nails or screws are very few. The 16" circular saw would be a handful to use vertically, won't cut full depth in the corners, and blades are very expensive. In place of the Prazi, a conventional electric or gas chainsaw could work.

On the Fire Dept, we cut through nails and etc. in roofs and walls with a conventional (non-carbide) chainsaw. But it dulls severely if you hit more than a few nails, and must be laboriously resharpened. However, I believe carbide chain requires special equipment to resharpen.

Instead of a dremel how about a tool of the "roto-zip" type?

Maybe my bet would be to use a "sawzall" with a bi-metal demolition blade made for "embeded nails".

Good luck,

Pete