Not on application, but you can phone up and ask them to raise the initial limit afterwards. If you tell them you want to transfer your existing debt onto the card, and close your previous card accounts, they may well be falling over themselves to help. Mind you, they may want proof you've closed your old card account(s) within N weeks/months of balance transfer as a condition of keeping the limit.
Depends on their assessment of your earnings potential (for them, that is) offset against the lending risk level. If you're about to drop many Ks of debt onto their card, they're hoping you'll overrun the zero interest period and start earning chargable interest.