\documentclass{jarticle}
\usepackage{enumerate}

\def\iroh{色は匂へど散りぬるを我が世誰ぞつねならむ
有為の奥山今日越えて浅き夢見じ酔ひもせず}

\makeatletter
\newcommand*\starwidthbox[1]{%
  {%
    \settowidth\@tempdima{*}%
    \hbox to\@tempdima{#1}%
  }%
}%
\newcommand*\itemstar{%
  \@ifnextchar[%
              {\item}%
              {%
                \item[%
                  \stepcounter{\@enumctr}%
                  \textbf{A}\csname the\@enumctr\endcsname
                  \starwidthbox{*}%
                ]%
              }%
}%
\makeatother

\begin{document}

\begin{enumerate}[{\textbf A}1\starwidthbox{}]%
\item \iroh
\itemstar \iroh
\itemstar \iroh
\item \iroh
\itemstar \iroh
\item \iroh
\itemstar \iroh
\end{enumerate}

\end{document}

from comp.text.tex
