Rappelling is inherently risky, given that you are committed to trusting yourself to an anchor, rope, rappel device and harness. To use anything less than equipment specially designed for the purpose is a bad idea.

Using para-cord for a rappel line is basically near suicidal since merely bouncing the weight of a typical adult male can generate forces way beyond the breaking strength of the cord. Not to mention the poor cut and abrasion resistance of the small diameter Nylon cord and the difficulty using such thin cord with any typical rappel device or technique.

All that being said, rappelling is not an inherently suicidal activity, climbers, cavers and others are not dropping to the ground to serious injury and death routinely, just occasionally.

In the instances that climbers do hit the ground during rapping it seems like anchor failure and going off the end of the rope are the two most common problems. Anchor failure is difficult to generalize about but going off the end of the rope is true user error and most easily prevented by tying knots in the rope ends.

Rappelling is not some mystical or arcane art form to be practiced a select few, nor is it such a specialize technical activity that only very highly trained elite people can do it successfully. It is a simple activity that needs some basic instruction and practice to understand. There are climbing schools, guides and clubs all over the country that can provide basic instruction.

Back, closer to the topic of self evacuation rappeling, it is possible to obtain, very light, compact functional gear. A good example is the Micro Rappel system from New England Rope Company.