From The Collaborative International Dictionary of English v.0.48 :
Plummy \Plum"my\, a. [From Plum.]
Of the nature of a plum; desirable; profitable; advantageous.
[Colloq.] "For the sake of getting something plummy." --G.
Eliot.
[1913 Webster] Plumose
From WordNet (r) 3.0 (2006) :
plummy
adj 1: very desirable; "a plummy leading role"
2: (of a voice) affectedly mellow and rich; "the radio
announcer's plummy voice"