There have been some interesting tang safety designs over the years.
Mannlicher Schönauers could be had with a "stalking (tang) safety" in addition to the flag safety. On the Mannlicher Schönauer the bolt is held closed by a leaf(?) spring behind the bolt handle with a bit of force, so unloading with the safety on would be possible. The Sauer 80 and 90 rifles - I think Colt sold them in the US - were both fitted with tang safeties, but they had a little button on the base of the bolt handle that would allow you to open the bolt with the safety on. Hand cocking rifles like the Blaser R8 and R93 also come to mind. In the uncocked position you just slide the cocking lever a little forward and can open the, otherwise locked, bolt.
