Hi alan, apparantly there's no reason why you shouldn't try growing your own coffee
Well, at least if you can believe this:
http://www.seedsofitaly.co.uk/product/679
Since S.O.I. are usually pretty open about things, I'm guessing this is real. However as with many slightly exotic things, I guess the devil is in the detail.
I was given seeds for a Bird of Paradise plant a few years ago. The instructions were very honest about the difficulty of getting them to germinate (involved carefully filing off one end of the seed coat on each seed!). Out of about 15 seeds, one germinated.
In a way I'm glad, as I later bought another plant and it's growing like a weed (currently split into 2 separate plants, each of which are over 4 feet tall and reaching for the ceiling!).
Colin