Few comments from a renting perspective:

Pleeease let us limit hash rate. It is cool to see 1GH/s fly over to a pool, but it is really not worth it--especially as you grow bigger. I would much rather be able to calculate and rent 100MH/s for 24hrs instead of getting everything you have for 25 minutes. This is especially annoying because most coins (esp new ones) are not PPS so unless you get incredibly lucky, you're throwing the money away.

This would also allow you to fill more than 1 order at once. If there are 7 people trying to throw BTC at you to rent rigs, it would be nice if you could take all of their money simultaneously instead of just 1 at a time (and risking that person going to another renting site to lock their speed down for set times). I think it would also help so you aren't ping-ponging the hardware around to tons of pools constantly.