straight top tubes, you mentioned it mostly for looks, but do you want more room to put bottles and frame bags and such?
whatever you get, I agree that if riding fully loaded is very infrequent, you will get more enjoyment out of a more lively bike for the rest of the riding season. This is exactly what I like about my 4 yr old Tricross, its not a true tourer but does a fine job with a reasonable load, but isnt a truck to ride the rest of the time.
No to frame bags and yes to two bottles (and possible a third on multi-day trips.
The real long trips won't happen often and again I pack light so that is accurate I don't really want a full fledged touring bike.