Sure we do it all the time. There are CPU limitations on the
amount of total traffic that can be pushed through a router that
is traffic shaping. I'm assuming because all the shaped traffic is
process switched. Also you will probably want to dedicate a router
to it.
Typically these are only useful near the customer connection, as
you can really only shape outbound packets. (unless you
traffic shape at your boarders, and have a "large" network, you've
already paid for the traffic by the time you discard it.)