Hardy Palms for Delaware?

I always wanted to grow a palm tree in my garden. However I live in Zone 7. As nature would have it there are a few palms that are hardy to this zone. This is not an isolated phenomena and there are a few websites devoted to the topic. I have complied a list here for future reference of some choices I am seriously considering.

• Trachycarpus fortunei or Chusan Palm is a palm from China that is hardy to -15C to -20C. There is one that has grown since the 1980's in the Brooklyn Botanical gardens so it seem like it might survive Delaware. It likes sun to part shade. This is an honest to goodness palm tree that can grow to 45 ft.
  

• The needle palm (Rhapidophyllum hystrix) is native as far north as South Carolina, but is hardy all the way to Zone 6. This clustering trunkless palm likes the summer heat but can survive to -23C. They don't get much large than a few feet.
  

• The Butia palm (Butia capitata) has apparently been grown experimentally in Delaware, but technically is only hard to Zone 8 or 9. I am wondering if having the creek in the backyard and being down in the valley next to it might mediate the lower temperatures in our yard and allow me to stretch the zone limits. It's hardy down to -12C. It also produces a fruit that is made into jelly in the South.
  

• The dwarf palmetto (Sabal minor) is native to the Southeastern United States which I could claim Delaware to be in if I needed to stretch it. It's hardy down to -18C and is a fan palm that grows to 3 to 4ft. The McCurtain strain grown in Oklahoma is one of the sturdiest strains of this palm. Wikipedia says (without citation!) it has been grown as far north as Rhode Island.
  

• The Chilean wine palm (Jubea chilensis) can survive temperatures down to -12C but does not like hot humid climates. I am not sure if that means that it cannot survive a humid Delaware summer. It would be cool to have this one because it is a close relative to the extinct palms of Easter Island, and that would be a good story to tell on a garden tour. The leaves are pinnate and it grows to 70ft tall. Probably too tall and too hard to get for the garden, but one can dream.
  

As to things that look like palms trees and are hardy to Zone 7; I already have some yucca growing in one of the beds, as do the neighbors. I am hoping that this year they flower. Ailanthus altissima (Tree of heaven), which looks like a palm and grows everywhere, I root out and destroy every chance I get, even in other people's yards, because it is invasive and nasty. My across the creek neighbor has a big stand of bamboo that I can admire from across the creek. I won't plant that in the ground because it can go crazy as well.

I am also torn between having these palms and going against the local and native plant philosophy we have been trying to stay closer to as the theme of the backyard. I think the them will hold as long as it doesn't stop us from getting a really cool plant or tree. No invasives though, that is a hard and fast rule.

Some other links with others trying to grow or find cold hardy palms and similar plants:

This Canadian site sells hardy palms.

Pennsylvania cold hardy palms

Hardy ferns and palms around Washington, DC.

Zone Denial, a blog devoted to this task.

More examples of growing plants north of their regular zones in the Delaware Valley are on this page and the following pages.

Does anyone out there have any experience growing hardy palms or trying to grow palms outside of their "regular" zone? Drop a suggestion in the comments please.