I have two Shimano crankset-based power metres for sale. Both are two years old and are cosmetically / functionally excellent. I have attached screen shots of both PM's to show that they are fully functional.
$800usd - Pioneer Dual-leg Dura-Ace 9000 power meter (11speed, 53/39, 175mm) In excellent condition and seldom used on dedicated time trail bike.

SOLD - Stages Single-leg Dura-Ace 7900 powermeter (172.5mm) In excellent condition. Used more often on my training bike, but still cosmetically and functionally great. I have updated firmware to latest version and purchased the improved battery cover that is stronger and improves battery contact. I do have an 11speed Ultegra 6800 crankset (either 50/34 or 53/39) that I can sell along with this for an additional $150.