I assume by you including Syria and Jordan on your route, that you will be entering Africa via Aqaba into either: (multiple choice, now)
c)Djibouti, via Red Sea/Jeddah
Could you not go via The Balkans to Turkey, then ship to Alexandria, and ride down into Sudan? (I hear Egypt is a hassle...) Or get to Cyprus and ship the bike to Israel, riding into Egypt via Sinai (I'm not sure if Egypt lets in people with Israeli stamps). From Haifa, you could ship to Port Sudan, Djibouti, or Mombasa, all avoiding the expenses of Syria and Jordan. I think there are lots of options, it depends on your availability of funds. I reckon that no matter what and where you go, you'll have to offset the costs with shipping expenses, customs, etc., As this site has so clearly illustrated, Egypt may want to be avoided. But travelling via Jordan/Syria, I assume you will be in Egypt? Also, what kind of a bike are you riding that these two countries add that much cost? B M W . . .
In regards to Sudan, you do not need a Carnet, but a "Letter of Credit" or Bank Guarantee of "x" amount of funds is needed, approxiamately $1000 (Canadian). ITs not real cash, but it guarentees that you have it, tying up money.
Travel Africa Overland...
scenicplanet.com offers route planning information, GPS points, shipping contacts and a "lovely array of travelogues". Well, one right now.