I second the Topeak Road Morph... it's not tiny, though... it definitely takes up most of the space on my (short -- 48cm) seat tube. Not something you would want to carry in a jersey pocket.
To pump to higher pressure (80 - 100 psi for road tires, eg), the ideal is a long, narrow pump chamber to provide a lot of PSI at the pumping end. So a long skinny pump like a Zefal HPX is really best if you can fit one on your bike. A pump aimed at mountain bikes tends to be shorter/fatter because it doesn't need to get the pressure as high.