\begin{calstable}
\colwidths{{3cm}{4cm}}
\thead{
 I'm a caption in the header\par
 \bfseries
 \brow \cell{head 1.1}\cell{head 1.2} \erow
 \brow \cell{head 2.1}\cell{head 2.2} \erow
 \mdseries}

\tfoot{
 \brow \cell{foot 1.1} \cell{foot 1.2} \erow
 \lastrule
 I'm a caption in the footer\par}

\brow \cell{body 1.1}\cell{body 1.2} \erow
\brow \cell{body 2.1}\cell{body 2.2} \erow
\brow \cell{body 3.1}\cell{body 3.2} \erow
\end{calstable}