Similarly there is the 'N' hotkey to cycle backwards.

Please read http://www.wesnoth.org/wiki/ReportingBugs#Guidelines_for_suggesting_features before posting feature requests.

Moving f.e. 30 units accross the map means 60 clicks every turn. 30 to select them and 30 to select the target. This can be tedius on larger maps where not much happens in the early turns.

Suggestion: let the player cycle between Prev/Next units with the keyboard, f.e. V and N.

Important: do not center the screen on the Prev/Next unit: do nothing if it’s already on the screen, just highlight it. Compromise: if it’s not on the screen just scroll it the barest minimum amount in order to make it show up on one of the edges.
Alternative: don’t scroll the screen at all, if the unit is outside the screen just pop up some hovering bubble at the edge of the screen in the general direction of the unit. The idea is to try to keep the screen in the target area as much as possible, so that it would be easy to move many units into the same area.

This way, moving many units long distance without much action is like alternating N - click, N - click, N - click, and as the screen stays largely at the same place, you don’t even have to move the mouse around much to move many units to the same area, making the process very quick and efficient.