Getting opinions from ppl with legendary status and working with pentest for a while - having weighed all the pros and cons, I've came to a disappointing conclusion. That it is lost forever. Hard to accept the truth sometimes)). But I think it's easier to include your BTC address in the signature and wait for somebody "to spare some cigarette" then to generate a required address/key pairs. Thnx everybody for the answers.
PS. Back up your wallet properly and use a good media resource to save it (different from your hDD). Otherwise you might end like this too((