From my research, while PS3/PSP/PSV hard copy games (not downloaded from the store) aren't region locked their DLC is locked to the store of the region the game come from,
example - Hyperdimension Neptunia Mk. II brought from the US has DLC which will only work if you buy it from the US Playstation Store and not the EU or JP stores

The whole point to this is having your entire trophy collection assigned to one account regardless of where you brought the game, not out of laziness but rather having a single profitable ID created by Playstation which has your entire trophy collection

i'm doing this under the basis that i want all my trophies on my EU Account while having a US Game with DLC

**-For PS3-**

1 - While not signed in, Run game so that Trophies are installed into system

2 - Log into EU PSN Account and Sync Trophies

3 - Log out of EU PSN Account

4 - Create US PSN Account (using a US Postal Address) and sign in

5 - Transfer Funds from visa/master card to PSN Wallet

6 - Buy DLC for US Brought Game, Download and Install (the install will occur after the download automatically and can't be canceled when it starts)

7 - Sign out of US PSN Account

8 - Play Game with DLC (DLC should work weather your online or not, didn't needed to be signed in to play Tales of Graces F DLC)

9 - When i want to sync my Trophies again, sign into EU PSN Account and Sync

**-For PSP-**

Same Process but i don't think there's any PSP game with trophies, i haven't found any

**-For PSVita-**

Apparently from what i read the PSN Accounts are bound tot he system so you can't just log out but so a full system restore in order to rebind to a different account

1 - While not signed in, Run game so that Trophies are installed into system

2 - Log into EU PSN Account and Sync Trophies

3 - System Restore system with memory card removed so to avoid an accidentally reformatting of it

4 - Create US PSN Account (using a US Postal Address) and sign in

5 - Transfer Funds from visa/master card to PSN Wallet

6 - Buy DLC for US Brought Game, Download and Install (the install will occur after the download automatically and can't be canceled when it starts)

7 - System Restore system with memory card removed so to avoid an accidentally reformatting of it

8 - Play Game with DLC (I don't have a PSVita but i assume DLC works for it much like the PS3 and you don't need to be online for it)

9 - When i want to sync my Trophies again, sign into EU PSN Account and Sync

now what i asking is confirmation that these work exactly as i have them, if not, please indicate what i need to change, i want it confirmed just in case if i have got it wrong and i can't reverse what i've done, i'm more concerned about the PS3 steps as have a US game which i know will have Trophies with it and i know there's DLC for it