You can try one of two things. First if this is just for display without printing, add a printer like HP Designjet 3500 that allows a very wide page.
Or you can insert a crosstab in the report header. You can't suppress it though (either the section or the crosstab object), although you could suppress individual fields and remove the grid so that is is invisible. Add a column that has many instances so that it creates virtual pages. Then insert a chart in RH_b and stretch it into the virtual pages. It does some weird stuff with the legend though.
-LB