On 2013–02–28 Matthias Weber wrote:

> -- without gaps between horizontal rows
> -- with text centered in the frames also in MkIV?

See Adityas answer for how to fix your current code.

> -- achieve the desired layout (exact dimensions, frames, no gaps) the right way, 

There is no “right” way. Here's how I would approach that:

\usemodule
  [database]

\definefont
  [MyBigFont]
  [Serif at 24pt]

\defineseparatedlist
  [MyTable]
  [before=\bTABLE, after=\eTABLE,
   first=\bTR, last=\eTR,
   left=\bTD, right=\eTD,
   setups=my:table]

\startsetups [my:table]
  \setupTABLE [split=yes, width=5cm, height=4cm, style=MyBigFont]
  \setupTABLE [each] [align={middle,lohi}]
\stopsetups

\starttext

\startMyTable
  Jim    , Mary  , John
  Patsy  , Bob   , Linda
  Mike   , Babsy , Bill
  Liz    , Dave  , Jenny
  Dick   , Sue   , Chuck
  Maggie , Joe   , Dolley
  Tom    , Lisa  , Chris
  Nancy  , Paul  , Betty
\stopMyTable

\stoptext


Marco