\makeatletter
\newcommand\bbrow{\brow\setbox\cals@current@row=
 \hbox{\vbox to 3cm{}}}

\newenvironment{decotable}{\begin{calstable}
\fontsize{15pt}{17pt}\selectfont
\cals@setpadding{Ag}\cals@setcellprevdepth{Al}
\cals@paddingL=0pt \relax
\cals@paddingR=0pt \relax
\def\cals@framecs@width{2pt}
\def\cals@rs@width{8pt}
\def\cals@cs@width{4pt}
}{\end{calstable}}

\begin{decotable}
\colwidths{{3cm}{3cm}{3cm}}
\bbrow
 \cell{left,\\top}
 \alignC \cell{center,\\top}
 \def\cals@borderL{0pt}\def\cals@borderB{0pt}
 \alignR \cell{right,\\top} \erow
 \let\cals@borderL=\relax \let\cals@borderB=\relax
\bbrow
 \alignL \cell{\vfil left,\\middle}
 \alignC \cell{\vfil center,\\middle}
 \alignR \cell{\vfil right,\\middle} \erow
\bbrow
 \def\cals@bgcolor{green}
 \alignL \cell{\vfill left,\\bottom}
 \def\cals@bgcolor{}
 \alignC \cell{\vfill center,\\bottom}
 \alignR \cell{\vfill right,\\bottom} \erow
\end{decotable}
