The TIAO Universal adapter is my favorite among parallel jtag adapters, and the reason is simple, all the pins are exposed. What this means is that it can be used as buffered, non-buffered and the parallel pins can be used directly, for applications like spipgm, it can be wired for blackcat, and several others.
This adapter can be purchased here
To read more about how to configure and wire the adapter go here
This is how we wire the TIAO Universal, the colorcoded wiring scheme is important, and usefull when trying to assist people using this adapter