[R] Custom LaTeX tables

[Werner Wernersen]

Hello,

I am very happy that I have Sweave and R to write my
papers. But I still have to do some tables by hand
since I have not found out how I can customize the
latex tables produced by R further (I mainly use
xtable()). Like for instance, I have a table which
needs an extra row every few rows as a group header
and sometimes I want some extra horizontal lines in
the table and also a multicolumn heading.

How do you guys cope with such cases, do you set the
table by hand in the end or have you found a neat way
to deal with this?

Many thanks and regards, 
  Werner