Fruit trees, pots and root bags.

Hi, I've got a few questions about container-grown fruit trees. I'd like a mini-orchard for my allotment, obviously space is at a premium and there are height restrictions etc. so I've gone for vertical cordon trees (apples, pears, plums, cherry, greengage) where possible. They are potted up for the time being. I'd also like to get a fig, a quince and a peach tree.

I have read in a couple of places that you can restrict the roots and therefore the height of the tree by just planting them in a pot sunk most of the way into the ground. This sounds like it would be ideal way for me to plant the cordons, as if I move to a house with a nice sunny garden in the next few years I might like to move a couple of the trees there. Is this correct? Has anyone tried it? Would a root control bag be better?
Just lifting the potted tree out of the ground after several years seems a little too easy to be true, I worry a bit about the roots busting out through holes in the bottom of the pot unseen and the tree growing out of control.

I've grown an apple tree in a pot before (from a seed as a kid...rubbish fruit but it was a pretty tree and I had it for 11 years) and it was OK with just one on the patio but a lot of watering in the summer and I'd prefer not to have to do quite that much watering for ten or so trees, also my site is a bit windy in the winter. I know they'd still need a bit of extra care but hopefully in the ground they wouldn't dry out so fast even in a pot. Plus they won't blow over.

Second, the fig and peach would be in containers permanently so I would be able to move them under cover or into sun as needed. Is there any reason why I could not put them in a rootbag, and then in some kind of planter for more stability (I was thinking of making a few nice wooden ones with slats on the bottom)? Would the solid walls of the planter interfere with the root bag if they touched? I don't want to buy a root bag to help the trees have healthier root systems and then just negate it with a planter that is too small and acting like a normal pot anyway.

Finally, one question about peach trees. For potted apples etc I've read not to use very dwarfing rootstocks because the pot will restrict them enough, so you should use a more vigorous rootstock. Does this go for peaches too? I know you can get the teeny genetic dwarf ones for patios, but if I planted a normal peach in a pot/bag would this work the same way as apples? I've not been able to find too much info on this but I've seen in the description for peaches on St Julien A "bring indoors or cover" on a few different nursery websites implying they can grow in pots OK.

OK that was quite long, thanks for reading if you slogged through that...