Well, you don't have to be innovative. I would say just make a good brief at the start which basically lets you do exactly what you want to. So just, if you are making it for yourself, say that your 'client' would like a frame built to given specifications which are unavailable from other manufacturers in the market. That way, you pretty much have a free choice. For example, I want to make a bass guitar, for me, I've wanted to do it for ana age and A2 DT is the best time me thinks, but to give the brief a new spin, I said that it would use modern construction techniques to build a ergonomic and playable device, based on a classic design with features and components chosen by my client. Basically, I want to make a bass, and all I did in that brief was to say I'm bloody well building it how I want. My teacher approved it as a bespoke item.