Vertical alignment of item label in itemize/enumerate lists

Question

I would like to align item labels vertically to the last line or to the vertical center of the item. Here is an MWE:

\documentclass{article}
\begin{document}
\begin{itemize}
\item item1 line1 \\
line2 \\
line3 \\
line4 \\
\item item 2 line1\\
2 line2 \\
\end{itemize}
\end{document}

This shows the item labels in the first lines of each items. I would like to place the item labels respectively:

1. in the last lines of each items, that is in line 4 of the first, and line 2 of the second item (aligned vertically to the bottom of the item);

2. between lines 2 and 3 of the first item, and between lines 1 and 2 of the second item
   (aligned vertically to the middle of the item)

Is this doable? (Either without or with enumitem package.)

Answer 1

If I understand well what you want, a simple \parbox with the optional argument for the vertical placement (the content of a \parbox is vertically centred by default) is enough:

    \documentclass{article}

    \begin{document}

    \begin{itemize}
    \item \parbox[b]{\linewidth}{item1 line1 \\
    line2 \\
    line3 \\
    line4}
    \item \parbox[b]{\linewidth}{item 2 line1\\
    2 line2}
    \end{itemize}
    \vskip 1cm

    \begin{itemize}
    \item \parbox{\linewidth}{item1 line1 \\
    line2 \\
    line3 \\
    line4}
    \item \parbox{\linewidth}{item 2 line1\\
    2 line2}
    \end{itemize}

    \end{document}