While I never did anything on the scale you are facing, I did mess up my credit pretty badly during my younger days after I lost my job and two credit cards were cancelled for non payment.
A few years later I had my dad guarantee a loan I took out for a replacement car after my old one was stolen. After paying it off I had excellent credit again. If you are young you don't have much to worry about, your credit will eventually fix itself, if you are older it might be tougher in the medium term.