Bottom line: Slic3r fails completely, MCslice works but has problems where solids cross, CuraEngine works but fails to connect some cross bars. Since I can load G code directly I will probably end up creating my own.
What makes this shape so difficult is the number of interior walls. It is essentially 60 rings held together with bars. Each ring has an interior, and all the cross bars connecting the rings create interiors. Where the bars cross each other the slicing engine has to decide what is inside and what is outside - MCslice calls the solid in between crossed bars "outside" because the surfaces cross there. So it does not print there. CuraEngine does it half the time, and the other half it simply ignores the bar altogether. It gives rows of bars and rings disconnected so the full shape is not one piece.
I've learned a lot, and I like the fact I'm pushing this technology to its limits. I know it can do what I want. It's just going to take a while. Especially since keeping the wife happy is a major factor!