Best hardy fruit tree for a big, big pot?

The previous owners of this house left us a HUGE plastic pot on the patio. I don't know what its capacity is, but it's two feet high and 28" across on top. When it's full of soil it's so heavy that one person can hardly shift it.

Since the patio is one of the sunniest spots in our generally shady yard, I'd love to plant a dwarf fruit tree in the pot. It would have to be something hardy in our zone (6b) -- I could wrap the plant, if needed, but there's no way to get that monster into the house. (I do have a couple of fig trees in smaller pots that I bring in.)

Any recommendations? I'm interested in something that produces lots of tasty fruit and is easy to care for (and preferably self-fertile). My front-runners so far are Geraldi dwarf mulberry or Northstar pie cherry, but I'm a bit concerned that I can't find any information about growing cherries in pots. Is it a bad idea?

Also, anyone have any experience with the newer "patio" sized peaches and nectarines?

I have my potted citrus plants on self built platforms with wheels. I put an hook on the platform and with a cut off broom handle and a C hook I just hook the platform and pull it into the garage. The Meyer lemon is one of the most cold hardy citrus that seems to put out fruit every year. I would suggest starting with it but don't plant a small plant in a large pot. Citrus like drying out between watering. Grow it in smaller pots until it gets large enough to put it in the bigger pot. Most citrus will only get as big as the pot you have it in. Also about every 2-3 years once in its final pot, remove it and cut off about an inch or two off of the roots and replant it. They are easy to grow if you don't over water them. As far as figs...they want to outgrow their pots and require drastic root pruning and top pruning as well annually and not like citrus they don't seem to get enough water as their roots tend to fill up a container rapidly.

I'd love to try citrus, but I don't have room to bring anything else into the house, and I doubt that a lemon tree can survive the whole winter in an unheated garage... can it? Your winters are probably quite a bit warmer than mine.

Meyer Lemon can survive down to 27 degrees...It can survive lower but will have damage to the leaves and branches. They will usually drop their leaves in winter and don't require much water. Also you can grow any fruit tree in a pot as long as you prune the plant and roots occasionally. I have grown peach, apple, mango and pommegranet in pots. It's best to get dwarf varieties so you don't have to keep pruning them as much. Give it a try all you have to lose is the price of a tree. Also in your climate, if you keep a potted plant outdoors in the frigid weather you may want to surround the pot with bales of straw to keep the pot from cracking.

Loligo, FWIW, I was talking with a gardening friend in north Georgia earlier this year. Her daughter has patio peaches in pots that do well and bear lots of fruit.