I don't think anytime soon. Apple seems to favor every other year on updating the iPod touch. It's been relegated to a backseat to the iPhone and iPad. I suppose if Apple releases a new bigger iPhone 6, then it would be a good time to refresh the iPod touch line. I don't believe it's a big seller for them any more, so it's become less important to push yearly upgrades. The iPod touch 5th generation is an extremely capable device. Have it and love it!
Oh and welcome to the community. Thanks for taking the time to join. I hope you enjoy your stay!