I haven't read the whole thread, so maybe this has been covered, but I figured I'd mention it as another data point.
This service is simple in that it doesn't require a proxy pool between the rigs and the renters' pools, which is good, but it's apparently not suited to offering one big 10+ megahash farm because you'd need network access to every individual instance of cgminer.
If this problem were to be solved, I'd give it a go, but managing 10 individual rentals is a much bigger pain than one large one.