My track bar and drag link are not at all the same length. But, they are parallel which isn't really that hard to do. I eye-balled by comparing the drag-link which is straight, to a cord tied from the frame side track bar mount. I just moved the cord until they looked parallel, marked and drilled.
I don't get any noticable bump steer. From what I have read, the length differences only comes into play at extreme drop or compression... I haven't had any issues and I know plenty of Jeeps that are different lengths and work fine.
Here's some good info:
http://www.bulletproofsteering.com/geometry.html