Any hand pump is going to be a trade-off between size/bulkiness and the ability to get enough pressure into the tire.

I carry this one: http://www.lezyne.com/road-drive (the "medium", which is pretty small) ... the other week I flatted 50 miles into a metric century, changed the tube and managed to get enough pressure into it to average over 20mph for the remaining 12 miles of the ride. I checked the next day and it was still at 80 psi, which is good for such a small pump.