Before we hired live-in help, we used to pay our housekeepers by the room. We would hire them as independent contractors (so essentially they were self-employed, as they had other houses they would clean throughout the week, as well), so we were not responsible for keeping in line with minimum wage, taxes, etc. Our smaller rooms would be $15 for a full clean (meaning the Guest checked out) or $10 for a refresh (just changing towels, making the bed, etc. if the Guest was staying over), and $5 more for the larger suites. This way, if they had a system and were able to clean quickly and efficiently, they would actually end up making more per hour. We would also allow them to do "extras" for more money, like if they wanted to vaccuum the stairs, or clean the main entrance, etc., and we would assign prices to each task. This was a great alternative, I think, to the hourly wages. It keeps them from dawdling and taking forever to clean rooms just to make a few extra bucks.
We also have comment cards that we slip under the doors of the rooms at the end of each Guest's stay. These allowed them to designate tips in addition to letting them vent, if needed, instead of spreading it on the internet later. We did (and unfortunately still do) have an issue with the housekeepers taking whatever cash was left in the room. On the surface, it makes sense that if they left cash, it's for the housekeeper. But there have been many times that the Guest meant for the tip to go to the Caretakers for serving breakfast, or they had broken something and this was their sheepish way of repaying us for it. We instituted a "all tips will go to the house and be redistributed on your paycheck" rule... but as you can imagine, cash is hard to prove it was taken unless you bait them with a fake tip!