Parallax announces JTAGulator:

https://www.parallax.com/product/32115?utm_content=bufferca961&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Designed by Grand Idea Studio, JTAGulator is an open source hardware tool that assists in identifying OCD connections from test points, vias, or component pads on a target device.

The product is currently on sale for the next few days, 15% off until 2015-08-31 (US$136 instead of US$160).