Whiteside make one that might work for you. Try #41959. 

George W.

http://www.woodcraft.com/Product/2008061/6511/178-Dx-1-CL-12-SH---Deep-Multi-Rabbet-Set-Whiteside-1960.aspx

 Thank you for the quick response to my problem. i have been to the website's mentioned but alas they will not ship to Canada. they would not even let me pay from here and deliver to an american address. so now i'am stuck with unfinished boat parts and no router bit to finish.  look's like i'll have to try and butcher a way around this. pity CLC don't sell the router bits for their boat plans.

  it's ok i have found another supplier that will post to Canada.  Not cheap this router after postage and tax comes to $83.00 US nearly as much as the plans to build the Northeaster.

I found one through a company called Magnate on Ebay for about $40 including shipping.  I did have to add a sub base to my router as the bit would not fit through the opening in the base(permanently affixed as it is a pounge router)  It worked well once set up.  John also suggested using a flush cutting bit with a guide - should work okay with caution at the ends.  Barry

I found that an electric planner will perform the rabbits just fine.  You can get one for the same price as one of these router bits, and you can do allot more with the planner other than rabbit.