As a naturalized citizen myself, I can tell you the process is pretty tough. I first had to come on a 3-year L-1 visa as specially skilled worker. This can be renewed by another two years. While in the US I applied for permanent residency (the green card is not green, by the way). I had to prove that I had skills not held by any American. My current job had to be posted 3 days in a row in Chicago Tribune with the applications going directly to the Illinois Department of Employment Security. They were the ones who would decide if any applicant were qualified, -and thus deny me my application. No, you can't tailor the job description to a particular person.
Broad categories for getting a visa seem to be:
-Specialized labor
-Head of a large, multinational corporation
-Investment. (Applicant must make a large investment in the country).
Neil