Method #2.
I realized after I coded this that there was a better way of proceeding, but it was too good of code to go to waste ;-)
ch1 = contour(...);
chc1 = findobj(ch1,'-property','xdata');
minx1 = min(arrayfn(@(h) min(get(h,'xdata')),chc1));
maxx1 = max(arrayfun(@(h) max(get(h,'xdata')),chc1));
xoff = maxx1 + (maxx1 - minx1) * 1.1; %second plot after a 10% gap
hold on;
ch2 = contour(...);
chc2 = findobj(ch2,'-property','xdata');
minx2 = min(arrayfn(@(h) min(get(h,'xdata')),chc2));
xoff = xoff - minx2;
arrayfun(@(h) set(h, 'xdata', xoff + get(h,'xdata')), chc2);
See also the material about xlim and labels in Method #1
