Thanks for the tips. These are good solutions but don't quite suit. Ideally, I'd like a giggable fx box that will double as a trainer. My phone needs are basically stone-age so I can't justify the cost of an iPhone
The GB10 comes close but is a bit limited effects-wise. I'm probably looking for something that doesn't exist. For one thing, the cost of the necessary internal memory for music storage would bump up the price of a multi-fx, only to add functionality that most players wouldn't want or need.