I wasn't going to reply, since I don't know the answer off the top of my head, and didn't feel like looking up the rules and forming an opinion. Then I realized the topic creator was Stalker0, who is ****ing awesome and to whom I consider myself indebted for all his work with skill challenges. Seriously, you should be on the WotC payroll, dude.
"Generally, you can’t take the same feat more than once, and most of the time you wouldn’t want to. A few feats, however, specify that you can take the same feat multiple times. That means you can apply the bonus from the feat to more than one situation—multiple weapon groups, powers you know, and so on." -PHB, Page 192
"Multiclass Versatility
You can choose class-specific multiclass feats from more than one class." -PHBII, Page 67 (emphasis added)
On PHB208, Initiate of the Faith, Student of the Sword etc, are listed under "Class-Specific Feats."
On PHB209, Novice Power, Acolyte Power, and Adept Power are listed under "Multiclass Feats."
Furthermore, on the table on PHB209, Novice/Acolyte/Adept power have "Any class-specific multiclass feats" listed as a prerequisite, even though these and the class-specific feats are listed on the same table under "Multiclass Feats."
My interpretation is that no, the Bard cannot take the power-swap feats more than once - he can take Novice Power, Acolyte Power, and Adept power once each. However, if he has the requisite class-specific multiclass feats, he can use each of the Novice Power, Acolyte Power, and Adept Power feats to swap to a power from multiple different classes.
So while you could not swap 2 bard dailies for a barbarian daily and a warden daily, you could swap a bard daily for a barbarian daily and a bard encounter for a warden encounter.