Have you tried drugs? Go to a shrink and convince him you have ADD (and who knows--maybe you do). All drugs for ADD are amphetamines, so it may take a fair bit of convincing before you get a prescription.
Not much finesse in that (possible) solution to your problem, but it sounds like you don't have many options.
I don't have numbers to back up my assertion, but I would guess Concerta (12 hour extended release ritalin) is the most widely prescribed. And a ritalin formulation would almost always be prescribed before moving onto Adderall. There is also Strattera, which is a non-stimulant ADHD medication that doesn't really work but sometimes parents ask for it so doctors try it.
Strattera basically acts on the norepinephrine system (like Reboxetine) as an antidepressant, doesn't it? If that's the case, I would think it would be effective for a good share of the inattentive-ADD (i.e. non-hyperactive) cases.
I don't know about the market shares, but, given that there seems to be many different types of methylphenidate for sale, I would assume that the market share for methylphenidate is non-trivial.
Not much finesse in that (possible) solution to your problem, but it sounds like you don't have many options.