I grow cordon fruit trees and they are very easy to grow and maintain. I would start with bare rooted maidens as these are quicker to establish and cheaper than pot grown two/three year old ones. As long as you pick the right type and rootstock for a restricted form of tree then you'll be fine. For apples I'd go for a M26 rootstock, or if your soil is poor or the variety you're growing is a less vigorous grower then MM106 rootstock would be better. Don't grow a tip bearing apple as these aren't suited to being grown this way. I would also suggest pears grown as cordons rather than plum or cherry which are probably too vigorous and not ideal for cordons (free standing, ie standard, or fans are better for these in my opinion).
Keepers nursery probably have the widest selection of apple/fruit varieties and different rootstocks than anywhere else. Their website is also a good reference for fruit types. You're probably too late for this season for bareroot choices though.
There are loads of apples and pears well suited to growing as cordons, Fiesta, Greensleeves and Scumptious are good choices for eating apples. Sunset is another one. Annie Elizabeth is a not too vigorous cooking apple that would be well suited too. Bramley, although a fantastic apple is probably a little too vigorous to be grown as a cordon.
If you did want to grow pears then Beth, Onward, Concorde and Conference are all fantastic varieties to grow.
As with all newly planted trees, keep them well watered in the first couple of seaons and if starting from a maiden don't let them fruit for at least the first year to give the roots a chance to get well developed to support fruit production. It's always very temping to let them fruit early but trust me you'll benefit by being a little patient.