What about a bike breakers? I did this on the QT a number of years ago and was turning excellent profit. Worked from home and used Ebay. The drawback was needing bigger premises coz there is good money in fairing panels and the likes. Got in to Harleys and couldnt be bothered after that.
For me the key was not to buy damaged bikes as the parts riders are looking for are the bits that get damage in accidents........ Was buying good roadworthy bikes and it worked.
With everyone feeling the pinch there will probably be a return to buying used parts as new parts cost much more.
Try it, see how ya get on and decide if its worthwhile or not. Even if its only a stop gap it could be an earner for ya