Is there an existing ECL developed to connect the Telescope DAM and SDL Tridion? I've heard there was, but I am not able to find any details.
yes there is an ECL connector for Northplains Telescope. It is developed by Tahzoo (formerly Hinttech)
It works with Tridion 2013 and provides nice features including search, metadata, direct links to Telescope assets, and Where Used. I would reach out to Tahzoo for more details as it is usually provided with an implementation package.