I can't reply to Cyphons coment for some reason, but there seems to be a problem with setting up the trade he describes. If it's succesful, he will then be stuck with a large amount of TND, which he has no use for and, due to the currency controls, can't convert to a currency that is useful for him.
That is leaving out the point that both the operators and the clients are willfully circumventing the law, which most governments don't appreciate.
Actually I'm a Tunisian, so the TND will be useful in the long run as an investment. But that still prevents me from reinvesting it into the business i.e. buying more BTC.
One way is to simply buy BTC from local sellers who perhaps bring BTC from outside the country. They take a cut and I add a markup before selling it back.
But there's another advantage I have. I'm currently residing outside the country, and if I do setup the business it will be funded using outside money. Because the company is funded externally, I can actually transfer any revenue it generates outside of the country.
As for your last point, that is in fact my biggest concern. The government could easily close down the company and its bank accounts at its pleasure. To avoid this, I think the safest option is to go with a purely decentralized market that simply connects buyers with sellers, but that will make it much harder to take a cut.
Anyways, I'm still thinking about the whole thing, and as you noted, it's not that straightforward.
You'd require some (substantial) investment, but you can always just mine them. Tunisia should have some fairly cheap electricity. Not sure how you can get the Asics there though. Maybe contact one of the sellers directly. They'll probably accept btc.
That is leaving out the point that both the operators and the clients are willfully circumventing the law, which most governments don't appreciate.