Why not get the wife her own bike? Or you could always go the sidehack route...just keep it in the wind!
 \\;
It also depends on the size of the dog...larger? Go for the sidehack. Small yapper? Have her ewar on of those front baby carriers and there's no problem.
I have a 1999 5x10 Wells cargo cycle hauler, paid $1300 for it and it has new aluminum wheels and tires. Trailer has a nose cone instead of the V. \\; I've only used it once, but still nice to know I have it just in case.
Just got back from buying a 6x10 wells cargo with the ramp in the back. \\; 2005 in great shape.. now I am looking at putting the condor wheel chock in the trailer and making it just right inside. \\; thanks for all the great info.