"Family" trees are very expensive for what you are getting (basically you are buying the growers time). If you only have space for one tree and there are no other trees in the area then they are a good idea as (assuming the grafter has chosen compatible varieities) they will mutually pollinate each other (except triploids, ask another question if not sure about this).
If you fancy having a go, buy a single variety then buy/scrounge a scion of another variety or two and have a go at grafting them yourself. Good sense of achievement when it works. If your grafts don't take you still have the bulk of the tree for that season and try again the next year. Alternatively you could buy the rootstock you want and graft the variety/ies you want onto it.
"Patio" trees are a good idea if you have limited space but again you will require at least two of each (apples, pears etc) unless they are self pollinators. I have yet to see a columnar tree that produces fruit anything like the advertising pictures. Growing in pots can work but need vigilance with watering and feeding, easy to lose an expensive tree if overlooked. I don't like fruit trees in pots having had poor results, much better in the open ground. If space is at a premium consider cordons or espaliers, again it is better to grow these yourself from 'maidens', firstly for the achievement and secondly the garden centres will strip your pockets for them.
No need to move into greenhouses for apples and pears, stone fruit could produce an earlier crop in the greenhouse but you will need to hand pollinate.
I would also look at other sources, I have used gb-online
http://www.gb-online.co.uk/prestashop/ and they have been very helpful. They do ship internationally but ask you to contact them directly for shipping costs. They probably carry a larger range than you would get at a local garden centre, though most of their stock is bare rooted so a bit late for this season, gives you plenty of time to remove the old tree. You can also select the rootstock you want.