wvj, in my opinion your original thought was on track, different machines for different processes. this is why I believe this:
in October I bought an alpha tig from ahp, it stick welded better than any machine I have ever used but I have since bought a Lincoln SW 200 and I like the tig function much better than the alpha. I also have a Lincoln 180C and I am completely happy with it. I fear if you buy multi function you will wind up lacking somewhere, I have 3 machines and am currently shopping for a stick machine because neither of my stick machines satisfy me with 7018's. my local AirGas will let me demo what they have in stock, which isn't much but it may be worth your time to hit your LWS up or even a votech to see if you can demo some machines. oh, and the reason the stick process is such a big deal to me is simple, I'm old and have been inhaling flux fumes from stick electrodes since I was 15, I am addicted.
good luck, hope it all comes together for you soon.
ps: advice I have a hard time following but it is good advice none the less---- buy once cry once !!
the heck with the duty cycle on the welder, tell me about the duty cycle on that grinder !!