The limitation is within the Frame Relay DLCI field. This field is 10 bits (until the Exended features to extend this address space) so you are limited to around 1000 DLCI's (some set aside for control functions). You should have no problem with 200 and change PVC's. There are also limits, although much higher, with ATM pvcs as well.
One other thing. If each one of your PVC's will require it's own sub-interface then you'll run into other (IDB Interface Descriptor Block) limitations as well. These are specific to IOS version and platform. The following URL shows these limitations:
http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps1835/products_tech_note09186a0080094322.shtml
Hope this helps you,
Don