Don't give up hope.
What you're asking for does exist. I've got it some where. Used it when I was preparing to go to Colorado in 1993. I'll look for it and before I respond I'll check to see if some one else provided you with the info. If you're just concerned about going from a lower altitude to riding at 10 to 12,000 feet, a rule of thumb is to reduce your jetting 10%. It works and gets you in the ball park. I live at 500 ft and took my KDX to the mountains this past year and didn't change a thing. Never fouled a plug and had plenty of power. In 1993 I reduced the jetting on my 250 KTM and it still ran way to rich. It just depends on the bike.