I've seen several former instruments of mine relisted at over double what I sold them for - at prices they struggled to sell at - and then struggle to sell again at the new higher price. I've had a Stingray, a Peavey Sarzo, an Ibanez Roadster, an L-1000 and, most recently, a Warwick Streamer LX, all show up at over double their previous sale price, usually a year or two after they left my hands. Are these collectibles? I don't think so, I just think Reverb has given a global platform to set ridiculous asking prices which then seems to affect the general prices of these things. Generally, though, desirability seems to really go on brand name, rather than instrument quality. There doesn't seem to be a correlation between how well built an instrument is and the size of the market interested in it. With more obscure brands, you might find an obsessive or two who are prepared to pay up but, if you want things to move, I think you're safer with the big-name unit shifters.