WordNet (r) 3.0 (2006):

finagler
    n 1: a deceiver who uses crafty misleading methods [syn:
         finagler, wangler]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "finagler":
   Machiavellian, behind-the-scenes operator, coconspirator, conniver,
   conspirator, conspirer, counterplotter, eminence grise, exploiter,
   gamesman, gray eminence, intrigant, intriguer, kingmaker,
   logroller, machinator, maneuverer, operator, opportunist, plotter,
   pork-barrel politician, schemer, strategist, wheeler-dealer,
   wire-puller