It can be done. I used to take my AI on my Civic with the bars just 25 inches apart. (EDIT: the bars may have had a 30 inch spread) The thing that made it work for me is adapting from Hobie's recommended way to carry the boat.
Hobie recommends carrying the boat upside down on the gunwales. However since they also recommend having the bars further then I had them apart, I looked at the best way to compromise.
I went out and bought Yakima MAKO saddles. (not the Mako Aero, but just Mako) They are a really nice design that doesn't pull the boat down onto it's hull, but instead hugs the boat with even pressure around the hull. They also give the boat some "suspension" so that hard bumps aren't absorbed by the boat, but instead by the give in the saddles.
I know others have all kinds of different ways, and I won't say they're bad, because they look great, but for me, these Mako saddles are the only way I'll carry my boat. I've got a new vehicle now and am able to set the bars over 50 inches apart, so I'm looking forward to seeing how well that goes, but given how well these saddles worked in less then ideal situations, I'm excited to see how well they do with a better spread between the bars.
The other thing that you might want to consider is looking into Yakima or Thule cross bars. They are stronger then factory racks, and in some cases they allow you to gain more spread between the bars. At the end of the day, if you are working in less then ideal situation, it's a matter of finding the best solution that you are comfortable with.
I hope that helps.
Here is a picture of the car (an AI with ama's and sail on the roof, and a Revolution beside it)
Here is a picture of the Yakima Mako saddles.