Well, if you want to, you can start off by making a custom creature variation that hinders muscle layers from slowing them down, and allowing strength and agility to boost walking, crawling & creeping speed. The following raws also hinders stealth from slowing them down, and allows them to sprint without any energy cost:
c_variation_fast
[OBJECT:CREATURE_VARIATION]
[CREATURE_VARIATION:FAST_BIPED_GAITS]
GAIT:type:name:full speed:build up time:turning max:start speed:energy use
use NO_BUILD_UP if you jump immediately to full speed
these optional flags go at the end:
LAYERS_SLOW - fat/muscle layers slow the movement (muscle-slowing counter-acted by strength bonus)
STRENGTH - strength attribute can speed/slow movement
AGILITY - agility attribute can speed/slow movement
STEALTH_SLOWS:<n> - n is percentage slowed
it would be interesting to allow quirky attributes (like mental stats), but they aren't supported yet
[CV_NEW_TAG:GAIT:WALK:Sprint:!ARG4:10:3:!ARG2:0:STRENGTH:AGILITY]
[CV_NEW_TAG:GAIT:WALK:Run:!ARG3:5:3:!ARG2:0:STRENGTH:AGILITY]
[CV_NEW_TAG:GAIT:WALK:Jog:!ARG2:NO_BUILD_UP:0:STRENGTH:AGILITY]
[CV_NEW_TAG:GAIT:WALK:Walk:!ARG1:NO_BUILD_UP:0:STRENGTH:AGILITY]
[CV_NEW_TAG:GAIT:WALK:Stroll:!ARG5:NO_BUILD_UP:0:STRENGTH:AGILITY]
[CV_NEW_TAG:GAIT:WALK:Creep:!ARG6:NO_BUILD_UP:0:STRENG
Now, we let the dwarves use these gaits. Let's also give them superhuman speed:
[APPLY_CREATURE_VARIATION:FAST_BIPED_GAITS:4:3:2:1:5:6]
[APPLY_CREATURE_VARIATION:STANDARD_CLIMBING_GAITS:4:3:2:1:5:6]
[APPLY_CREATURE_VARIATION:STANDARD_SWIMMING_GAITS:4:3:2:1:5:6]
[APPLY_CREATURE_VARIATION:STANDARD_CRAWLING_GAITS:4:3:2:1:5:6]
The first step is really not necessary. If you want to, you can just leave the first line changed in the dwarf creature to STANDARD_BIPED_GAITS and just modify the values passed.
I believe these raws should let the dwarves "sprint" at 8700 kmph. At any rate, they're freaking fast.
Edit: Essentially, the values passed are delays for movement. you could set them to 1:1:1:1:1:1 and they should always move at 8700kmph, even when crawling around. Currently, they should walk at around 2175 kmph, jog at 2900, run at 4350 and sprint at 8700. Strolling should be 1740 and creeping should be 1450. These calculations are based on the text file "gaits.txt", which I believe state that a delay of 100 is equal to moving at about 87 kmph.