joe,
the simplest most effective solution is to roast fresh and then bag the beans in some one way valve bags as quickly as possible and remove as much of the air as you can. Re-seal the bags after each use and again try and remove as much air as possible. In all likelihood, for a few weeks, this will still result in your beans being fresher than any you are likely to be able to buy. If you need some bags, try either hasbean or anothercoffee in the UK. The important thing is to reduce air contact as much as possible.
Most people here probably use their beans within 10 days or so of them being roasted, but we're talking about ideal situations here. I suppose the other thing you could try is to roast on site using one of the more "hands on" approaches documented on TMC (ovens and frying pans spring to mind). If we're talking about longer periods of time, then I would probably just order them pre-roasted via the net from somewhere like hasbean. To be frank you're unlikely to get better quality than that anyway, even if you roast them yourself, though of course it is not as much fun!
D