I would agree with rback33 and Farmwithjunk, go for a tractor drawn all crop,
one with only a 6 or 8 foot cut won't take much more than an easy day or two,too harvest 16 acres. If bags are still available and you find a machine with a bagging attachment, although a lot more work bags may be the way to go, also the grain could be easier to sell in bags if you are in an area where there are a lot of small holdings.
A lot of replies advise the use of a contractor, (they are possibly correct) but don't be put off , what you really wanted to know was, what would be a suitable machine and where to obtain one.