I used this so I can guarantee it works, it's absolutely brilliant Plus it kickstarts our skyrim section with help
You may want to add in that this also works in solitude which is the location of the most expensive house (25,000) I did it myself so it does work. I believe it can also be done for all of the houses.
It is worth saying this works for ALL houses as long as there is a storage container nearby (there is in all stewards quarters) and it also works for all of the upgrades for a house the same way.
This method basically can be used for ANY item you are buying so long as there is a dialogue delay between pressing "buy" and the gold being taken, and of course that there is a container to store your money in.