Positioning elements of the heatmap.2 plot can be done using the layout parameter(s).
layout(mat = lmat, widths = lwid, heights = lhei)
I get a pretty acceptable heatmap plot using the following.
heatmap.2(x,
Rowv=NA,
Colv=NA,
scale="none",
main="This title will be cut off by the white space where the non-existant key is supposed to go.",
col=gray((255:0)/255),
dendrogram="none",
trace="none",
key=FALSE,
lmat=rbind(c(2),c(3),c(1),c(4)),
lhei=c(1,1,9,0),
lwid=c(1)
);
Please refer to ?layout
or this answer on Stack Exchange for more details.