Sounds like maybe the S500 might be your best bet for right now. But for the future, have you seen one of those HX250's other than pics and videos? We have a local dealer here and I saw one at a tool show they put on. Those are sweet little machines! I would definately keep that on my Radar If things keep going well for you. And hopefully they do. Good Luck.
Have not seen one in person, just videos and pictures. Got a quote with the options broken down. Really is appealing especially when looking at the 650, it isnt much more with its ability to expand in the field. But it starts at 2x the cost of a 500 so will be weighed.