You *can* increase combat / treasure finding speed as fast as you'd like

[hapveg]

Nope, this only affects the animation speed of units in combat.

I think the out-of-combat movement speed can be changed, but in a different file.

For example, "archmage.atom" has all the unit abilities and the in-combat animation speed, but "army_archmage.atom" seems to have the out-of-combat data (including turn_speed, walk_speed, run_speed, aggro_sound).

I've only modded the in-combat animation speeds, so can't say how accurate the "army_archmage.atom" hunch is.