After searching quite a bit- Perhaps a Spyderco Shabaria.
It's the C59BMP Shabaria, second production run with the screwed construction and the open back.
My small collection: http://www.araneomorphae.de
"I spent a lot of money on booze, birds and beautiful knives. The rest I just squandered."
Slightly modified, R.I.P. George Best.
Thanks very much to all of you!