Indentured servitude has, in some ways, distinct advantages over slavery.
Slaves, while not paid wages, are large capital investments, very expensive to buy initially. Indentured servants don't require any large up-front capital investment, and payment is deferred until the end of their contract (in the English colonies I believe this was about 7 years, generally-speaking)
However, it is the end payment which was causing problems for the system of indentured servitude. The contract stipulated that the master, upon the fulfillment of the contract, give a certain amount of his land to the servant. However, the contracts generally said nothing about the quality of said land.
This, after 69 years, created a problem in the colony of Virginia, whereby you have a burgeoning class of hard-scrabble, poor farmers occupying land which was either exhausted of its nutrients (a product of the ever-popular Virginia pastime, tobacco cultivation) or was never particularly fertile in the first place. These lands were of course far from the relatively wealthy coast and thus on the oft-harried western frontier, creating near-constant clashing with the interior tribes.
Now, according to Wikipedia (take that source as you see fit) there are other factors playing into Bacon's Rebellion (the aforementioned problem for the colony of Virginia). Overproduction of tobacco drove the price of tobacco down, which meant that these poor farmers who themselves got into the tobacco racket after their indentured servitude had expired, could no longer turn a profit once in competition with the "Tidewater gentry." This combined with the Navigation Acts, the attempt by the Virginia Colony to diversify its heretofore tobacco-based economy and a need to defend the frontier against Indians and the odd Dutchman resulted in rather high taxes.
So Bacon's Rebellion, the last nail in the coffin for indentured servitude in North America, was the result of high taxes on a class of once-indentured farmers already pushed to the brink by Indian attacks and poor land.
So, given this, one has a few things one could do to created a sustainable system of indentured servitude.
1) Diverse economy early on. I'm not entirely sure how this is possible, unless somebody wants to ISOT a mother-lode of gold into the Tidewater area.
2) More responsible indentured servitude contracts, which would ensure medium- to good-quality land upon the release of an indentured servant. Not sure what PoD would be required for this, this delves into legal history.
3) Ameliorate the pressure applied by the frontier Indians. You have any number of ways of doing this.
4) Somehow avoid the Navigation Acts. This put a lot of strain on farmers of all classes in the colonies.
Just my $0.02.
