Equation environment for centered, equally-spaced columns of expressions

Ok, the following is probably as dirty as it could ever get, and I have to admit I patched it together by trial&error, but at least it might invoke the spirits-that-be to find a better solution.

Try

\documentclass{article}

\usepackage{amsmath}

\usepackage{etoolbox}

\makeatletter
\def\calign@preamble{%
   &\hfil\strut@
    \setboxz@h{\@lign$\m@th\displaystyle{##}$}%
    \ifmeasuring@\savefieldlength@\fi
    \set@field
    \hfil
    \tabskip\alignsep@
}
\let\cmeasure@\measure@
\patchcmd\cmeasure@{\divide\@tempcntb\tw@}{}{}{}
\patchcmd\cmeasure@{\divide\@tempcntb\tw@}{}{}{}
\patchcmd\cmeasure@{\ifodd\maxfields@
  \global\advance\maxfields@\@ne
  \fi}{}{}{}    
\newenvironment{calign}
{%
  \let\align@preamble\calign@preamble
  \let\measure@\cmeasure@
  \align
}
{%
  \endalign
}  
\makeatother

\begin{document}

\begin{calign}
  A & \min(B,Z) & C
\\
\nonumber
f & g & h
\end{calign}

\end{document}