Good questions Bill, got me thinking a bit, let me answer them:
My last post dealt with the finishing process. Now I would ask you about the building process.
How will you accurately break down the plywood sheets? Table saw or circular saw and straight edge? - combination of the 2, I can't rip handle a full 4x8 sheet on the saw, but I'm ok with handling semi large pieces
Does your saw/shop allow for a 24" rip and support both in and out of the saw? - I can swing that
Do you have to carry the sheets down stairs and will this be a problem? What about a helper? - nope and yep
A router guide/jig to make dados across the 24" width for the bottom and for the upper cabinets would be handy. - got it
How's your supply of clamps? - moderate, would probably pick up a few more. But you can always have more
Do you have a brad nailer? - yep
How about a rabbeting bit or dado head for your table saw to set the back panel into? - yep
Will any of the sides be exposed to the room and be visible at the rear so the finished wood runs all the way to the wall? - The lower cases could have 1 side showing, or maybe none depending on the final lay out. I would have a tall pantry that would have exposed sides in the middle area. Back are all against the wall.
Can the toe kick be separate base that the cabinets sit on? - sure it could be, I think that would make case construction easier.
What about drawer slides...what brand and type? - No idea
What style of doors, raised panels with molded details, Mission style?
If you need routed details then there will be some hardwood cost involved, maybe the cost of new cutters and a router table? - I'm toying with ideas, I was thinking either raised panel, or just maybe a little detail on the edges and a flat panel in the middle. I have a router table.
And what about finishing? Method, material and space? - I was thinking maybe just a water based poly. I have all the equipment to spray and could do it in and around the garage.
The answers to these questions will help you decide what to do as well as what others have said regarding cost...not really that much of a factor in my opinion. The difference between cheap ply and better is probably $100.00, if that.
My biggest concern is the amount of time to do them all as well as the general construction method. I know that they are just boxes and drawers, but I always like to know all the details before I tackle a project