my RTW plans changed dramatically earlier this year, i was planning for 2013 in Africa, after spending some time with Chris Scott personally, all his advise was avoid west africa, mainly french speaking areas for the near future, and now there are new problems in the north east and arab states, i would research this area very carefully, and be aware that things can change on a daily basis, sometimes hourly.
i lived in Kenya and Morocco so have hands on experience with Africa
also you may want to read this ride report - http://advrider.com/forums/showthread.php?t=710660
they just went around africa, some days only managing single digit KM days, it took them almost a year
also you don't mention a Carnet at all unless i missed it, this all needs to be calculated in to your travel costs
on a brighter note look into the Isle of Man TT races if you are into motorcycles this is a must see event in early English summer