Debit Card vs. Credit Card linked to checking?
 

Is there any way to tell just by the card number whether a card is debit or credit?

Are there credit cards out there that are linked to a checking account? For e.g., let say if I return something on my CC and as a result the account is positive I have the ability to transfer the funds out to another bank or write a check from that account.

Conventionally speaking these cards would be considered debit cards, but I am trying to figure out if there are cards coded as credit cards that are linked with checking/saving/money market accounts.

I know of at least one bank that will let you CA their CC to your checking without a fee, effectively doing what you are asking.