Have you thought about a cruise? There are some wonderful destinations out there, and a cruise is an excellent way to S-T-R-E-T-C-H your travelling dollar!
September is also a "shoulder" season, so you can probably find some really great deals!
Let us know what you and Mr. Mox end up deciding.
(PS: greeklawboy and I went to Maui and Big Island for two weeks during our honeymoon. It was amazing! While we opted to splurge, I *do* know that there are also many less expensive ways to visit Hawaii if your heart is set on it.)