This all sounds so easy. Why don't more people do it?
For starters, most, 401-K plans allow only one outstanding loan. Thus, if you take one out for $20 grand and later need another 20 g's; sorry, no loan for you until you pay off the one you have. Not always so simple.
Only nice thing I found is that if you legitimately retire from a COmpaNy, you can withdraw from the 401-K as if you were 59.5 years young, even if you are younger. You save the 10% penalty "tax".
By "retire", you have to hit 85 (in my case, those bastards raised it to 86) points. 1 point for each year of age and 1 point for each year of service to the employer.