If you are going to use a Yukon make sure it is the HD not the LT, with the LT you could have some issues with suspension, Trans, rear end.
I can testify that the shorter WB is not a good thing, I have a 07 GMC 1500
Ext Cab Short bed and I can definately tell you that you will get the dog wag as well as turn/push issues.
Although my veh does pull my 31 Soveirgn, I would much rather have the longer WB such as in a Ext Cab Long Bed or longer, and I definately want to have at least a 3/4 ton, (Chev/Dodge/GMC 2500, Ford F250).
I now have my GMC up for sale so I can move to a better vehicle, if I can not sell it then once I have my motorcycle sold I will take the loss and trade. Hope to have it done by the time my trailer is done at AS in OH in May. What I am getting now is going to be either E250 Conversion Ext Van or a F250 Crew.