Jack, in your price range and with the functions you want you are probably looking at AHP or maybe Everlast unless you want to get down to something along the lines of Lotos.
I had an AHP AlphaTig 200 and it didn't go well for me and after that I decided a true ac/dc multi process machine wasn't in my budget so I have a Lincoln 180 mig machine w/ spool gun, a Lincoln square wave 200 and my old faithful Lincoln 225 AC.
I am still looking at other machines and talking to folks about theirs and if your not hung up on AC tig you might want to research the ESAB Rebel 215 IC. you can dc tig with it but no ac but you can get your aluminum welding done with a spool gun, the total cost with the spool gun will put you around 1700 bucks.
I had some issues with the stick function of the square wave at first but I guess it was the rods because since then it has done well for me, I used it Saturday to build a stair hand rail and it ran smooth as silk.
I understand wanting an all in one but for our resources I don't think it is out there yet so I would suggest making up your mind which process is most important to you and start looking from there, I personally feel like if you are only going to have one machine for garage type work and light fab you will be happier with a mig/fcaw machine with a spool gun for your aluminum work.
good luck and I look forward to seeing what you decide on.
the heck with the duty cycle on the welder, tell me about the duty cycle on that grinder !!