Points usually take at least 2 or 3 days after checkout to appear, so there's no chance of you using the points earned from the first 5 cash nights to pay for the last one.
So its a non-runner I'm afraid.
As IAHFLYR has pointed out, points and cash might help you. For 17,500 points and $75 you can get that night. However the new points and cash scheme isn't yet running we don't know what availability will be like.
Yes, I thought it was odd that it was only 30,000 points per night, but still got fooled!
A good idea might be to automatically lock threads barring further comments after, say 90 days inactivity, that way valuable/historic information won't be lost, but these kind of threads wont accidentally emerge from the deep to catch us out!