This is possible since Burst of Speed doesn't break Stealth any more and is also spammable due to it's low 30 energy cost.
You also need the talent nightstalker, which does stack multiplicatively with other speed increase abilities.
I don't know if a boot enchant or anything else would increase movement speed even more.
Calculation: 100% * 1.2 * 1.7 = 204%
1.2 comes from the 20% of nightstalker, 1.7 comes from 70% of burst of speed
Nightstalker works differently (it stacks multiplicatively), probably due to where it came from traditionally: it used to reduce stealth movement speed penalty, which was not considered a speed increase.
That's 4% faster than a rogue on a mount or most other mounted classes, and it's permanent. Outside of BG's or Arenas, that one guild perk still makes mounted players faster though.
It's fun to use it in the Alterac BG :-) If you have good pathing, you can stay ahead of most other players with our +4%, if they are not DK or Pala or have some exotic item or skill (hunters with glyph?).