While the HN discussion[1] has some great comments on challenges faced by early employees and sama's post has discussed some alternate structures that benefit early employees (and founders); the discussions is a little light on resources on how a founder could make use some of these structures and any challenges they may face as a consequence.

The obvious choice would be to ask a lawyer - unfortunately most lawyers I have spoken to do not have an opinion/advice or have not done this before or find the idea ludicrous.

Would you use back-weighted vesting at your start-up? If not why?

[0] http://blog.samaltman.com/employee-equity [1] https://news.ycombinator.com/item?id=7610527

(For example, 10% of the grant vests after the first year, and then 20%, 30%, 40% in the following years.)