I am wondering if anyone is doing this since we are about to embark on
this journey.

I'm sure most of you also feel the pain of the tape budget just as we do
so we're looking at ways to cut it down.  The most obvious way is tiered
backup services.  My thoughts on this so far:

Gold - required restore time of 1 hour
        Full backups to tape weekly
        Cumulative incrementals daily
        Data replication to separate data center
        Cost/MB = $<some high # here>

Silver - required restore time of =<12 hours
        Full backups to tape bi-weekly
        Differential incrementals daily
        Cost/MB = $<smaller # than Gold>

Bronze - required restore time of up to 48 hours
        Full backups to tape quarterly
        Differential incrementals daily
        Cost/MB = $<much smaller # than Gold>

None - no backups required

I plan to run with some version of this but would like to know if
someone has already done this and can offer some tips.

Thanks.

~JK