>Not to mention that coding style may require that function calls broken to 2 lines must have the arguments aligned at the opening parenthesis.

That doesn't result in any problems with using <TAB>s, unless the coding style also requires you to replace all (leading) sequences of N spaces with with a <TAB>, which is, IMO, quite brain-dead. For example,

    if (cond) {
    <TAB>foo(1,
    <TAB><SP><SP><SP><SP>2);
    }

looks fine regardless of the width of <TAB>.

Admittedly, your first problem remains; a problem with dumb editors. In truth, your editor could well signal if your lines exceed the limit (indent-width*indent + rest) you have set for your project, just as easily as it can draw a line at a column.

The harder problem is that you need a context-aware editor for it to help you with indenting. Most editors are incapable of that by default.