So from the grey to the white ones.

Next are the brown. 36mg is still a pretty light dose for an 11 year old, so he might go to the brown 54mg. Focallin is a good choice as well. Or a small dose 5mg of regular Ritalin can help in the afternoon with homework.
As for the rebound effect, ask your doctor about prescribing Remeron 15mg at dinner time. It is a drug used to treat depression but has the side effect of making you sleepy and increasing appetite. Woohooo! Not so good for depressed people, but for children on Concerta that have a hard time sleeping and cannot keep weight on its a WONDERFUL thing. It also helps them to calm down and relax before bedtime. Our psychiatrist is one of the doctors that has been really prescribing this for the side effects and has seen great results.
I have learned the hard way, that many people tend to have an opinion about the parenting decisions I have made with my children in regards to treating their ADD/ADHD, so I will probably not be checking back on this thread. If you have any questions or just need an experienced ear, please send me a PM.