The
Northern Lite 6'10" would be my top pick if money was no object, but it would extend a bit.
Also check out the Pastime 640LT, Travel Lite 690W, and
Panther Sierra and Cascade.Four wheel campers used to make a hardside Hawk that would have zero overhang, but I don't see it on their web site any more. I'm sure they would build one for you if you wanted though. I saw one for sale used around here the other day -- very rare.
As mentioned earlier, the Six Pac S650 and T100S are short, but I'm not sure exactly how short they are and they are only available used. Four wheel campers seems to have something to do with six pac and still has the site going, but is not making them and I don't think they will anytime soon because it's been that way for years.
Lastly, the Sun Lite 690 is a great option if you can find one used.