small fruit tree

This is not really my area of expertise, but there used to be available the "Ballerina" hybrids, which only get that tall, but on one stem, so it grows straight up and takes up very little room. You might have to do some research though - I'm talking ten years ago now, and I believe there weren't many varieties of apple in this form available at that time.

Also check out a previously posted question similar to yours, asked by Scotkat, currently on the page before your question here, about growing fruit trees in pots - answer might be useful to you.

You should go for growing a dwarf or patio fruit tree. Garden centres sell them. You need to look for M27 rootstock, they grow to around 6-7ft and are happy in a decent sized pot.
M9 root stocks are slightly bigger, and would need a larger pots.
Just remember to keep them fed and watered.

http://www.rhs.org.uk/growyourown/fruitadvice_rootstocks.asp

- gives you an idea of the types of rootstock and sizes they grow too and types of rootstock depending on fruit you wnat to grow.

http://www.rhs.org.uk/advicesearch/Profile.aspx?pid=359
Is a bit more helpful

Any garden should be able to help but make sure they know and cancan reassure you it is M27/M9! It shoule be on plant label

They also need to be in the same pollination group or self fertile. The GC should also be able to help

some tomato plants can get upto 7ft

Yep, that's the answer I meant - Nickyt08's, which she/he's kindly repeated here.

Saves trawling through finding it! Im a he!!!! I didnt mean to put the 'Y' but its next to the 'T' and got typed too!!!!