Are there any regs that prohibit a bank from requiring a checking account in granting a loan (consumer or business)?

You are allowed to do this under the exceptions to the antitying provisions in Reg. Y.Traditional services can be associated/required.

See Reg. Y.
"b) Exceptions to statute. Subject to the limitations of paragraph (c) of this section, a bank may:
(1) Extension to affiliates of statutory exceptions preserving traditional banking relationships. Extend credit, lease or sell property of any kind, or furnish any service, or fix or vary the consideration for any of the foregoing, on the condition or requirement that a customer:
(i) Obtain a loan, discount, deposit, or trust service from an affiliate of the bank; or..."

First published on BankersOnline.com 2/17/03