SDAPS class patch to enable row coloring. With the issue that checkboxes move slightly (0.0001pt or so) which changes the survey ID.

gistfile1.diff

diff --git a/tex/sdaps.cls b/tex/sdaps.cls
index 89abf1e..602b1c8 100644
--- a/tex/sdaps.cls
+++ b/tex/sdaps.cls
@@ -120,7 +120,7 @@
 \RequirePackage[T1]{fontenc}
 
 % color
-\RequirePackage{color}
+\RequirePackage{xcolor}
 
 % Symbols (boxes)
 \RequirePackage{amssymb}
@@ -191,6 +191,37 @@
 % Code 128 implementation in plain TeX
 \include{code128}
 
+% Load Row coloring code (this requires a workaround)
+\AtBeginDocument{%
+  % The default value of the defines, simply do not do anything about
+  % row coloring.
+  \def\@sdaps@rowcolor#1{\relax}%
+  \def\@sdaps@rowcolors#1#2#3{\relax}%
+  \def\@sdaps@showrowcolors{\relax}%
+  \def\@sdaps@hiderowcolors{\relax}%
+  \def\@sdaps@multicol@fill@workaround{\relax}%
+  %
+  \@ifpackageloaded{colortbl}{%
+    % Is the rowcolors command defined?
+    % If yes, enable all the rowcolor usage in SDAPS.
+    \ifx\rowcolors\@undefined%
+    \else%
+      % Use the rowcolors command
+      \let\@sdaps@rowcolor\rowcolor%
+      \let\@sdaps@rowcolors\rowcolors%
+      \let\@sdaps@showrowcolors\showrowcolors%
+      \let\@sdaps@hiderowcolors\hiderowcolors%
+    \fi
+    % This is a nasty little workaround. colortbl does not support fills
+    % inside multicolumn cells. However, adding corresponding skip *after*
+    % the \multicolumn command works around this issue.
+    \def\@sdaps@multicol@fill@workaround{\hskip 0pt plus -1fill}%
+  }{%
+    % Nothing to do
+  }%
+}
+
+
 % http://www.tex.ac.uk/cgi-bin/texfaq2html?label=isitanum
 \def\IsPositive#1{%
   TT\fi
@@ -679,6 +710,10 @@
 \definecolor{sectionbgcolor}{gray}{0.8}
 \definecolor{sectionfgcolor}{gray}{0.0}
 
+\definecolor{choicegroupheadcolor}{gray}{1.0}
+\definecolor{groupevenrowcolor}{gray}{1.0}
+\definecolor{groupoddrowcolor}{gray}{1.0}
+
 % Execute sdaps.opt file to allow SDAPS to override any options
 \InputIfFileExists{sdaps.opt}{}{}
 
@@ -942,7 +977,8 @@
   \question{#1}%
   \protectedimmediatewrite\sdapsoutfile{QObject-Head=\arabic{section}.\arabic{subsection}. #1} %
   \setcounter{choicegroupnumchoices}{0} %
-  \global\def\@sdaps@choicegroup@start{\tabularx{\linewidth}{X*{\thechoicegroupnumchoices}{c}}} %
+  \@sdaps@rowcolors{1}{groupevenrowcolor}{groupoddrowcolor}%
+  \global\def\@sdaps@choicegroup@start{\tabularx{\linewidth}{X*{\thechoicegroupnumchoices}{c}}\@sdaps@rowcolor{choicegroupheadcolor}} %
   \global\def\@sdaps@choicegroup@boxes{} %
 }{%
   \ifnum\thechoicegroupnumchoices>-1 %
@@ -960,6 +996,7 @@
   \ifnum\thechoicegroupnumchoices>0
     % Move to the next line (as it is not part of the @start macro)
     \\ %
+    % Enable row colors
     \setcounter{choicegroupnumchoices}{-1} %
   \fi %
   \protectedimmediatewrite\sdapsoutfile{QObject-Choice=#1}%
@@ -1002,6 +1039,7 @@
   \protectedimmediatewrite\sdapsoutfile{QObject-Head=\arabic{section}.\arabic{subsection}. #1}%
   \@sdaps@markenvactivetrue%
   \@sdaps@generatemarkboxes%
+  \@sdaps@rowcolors{1}{groupoddrowcolor}{groupevenrowcolor}%
   \tabularx{\linewidth}{Xr*{\themarkcheckboxcount}{c}l}
 }{%
   \@sdaps@markenvactivefalse%
@@ -1149,7 +1187,7 @@
       \fi%
       \addtocounter{textboxnum}{1}%
     \endgroup%
-  }%
+  }\@sdaps@multicol@fill@workaround%
   \ifthenelse{\thechoiceitems>\themaxchoiceitems}{%
     \setcounter{choiceitems}{1}%
     \\%