Is there any prohibition against paying the entire amount of interest on a time account upfront at deposit time rather than quarterly, monthly, yearly, etc?

Only if it has a maturity greater than one-year - then you have to contend with 1099OID reporting.

And still impose the minimum early withdrawal penalty if the funds are withdrawn in the first 7 days.

There's a bank in this market that will give you a gun today in lieu of interest for your time deposit. So the precedent has already been set for pre-payment of the interest.