Yes, I have used a cleaner/wax. While they are not bad by any means, they will never give the same results as a multi-step process, but I have had good results on a non-clear-coated car with Meguiar's #6 Cleaner/Wax. I've used it by hand as well as with a PC and had good results.
Just keep in mind that you won't get the same results that you would if you were to perform all the steps at once.
Good Luck!