I imagine it could be practical post-60 with the assassin trait, but in all honesty I'd like to see 4 thieves, a nin, and a bard try to xp. The thieves could give their trick attacks to the ninja or one of the thieves standing opposite the ninja. SATA when applicable to one of the two, preference to the ninja. Skillchain...probably wouldn't need it with 4 thieves doing 300 damage 8 times a minute with that bard, disregarding weaponskills. I imagine half the thieves could use their weaponskill during one fight, and the other two the next fight.
So that's two thieves doing 700+ damage per fight with sa/ta/weaponskills, and two thieves doing 400 damage per fight with sa/ta's. That's 2200 damage in 30 seconds. Throw in DoT and the ninja, and that'd probably work well while keeping the tactics pretty simple.
But until 60 that junk would be a burning nightmare of chaos. If you screw up, your trick attack misses and it all derails >.<