1. A system, comprising: a plurality of computing devices configurable to implement a plurality of resources of a provider network; and one or more computing devices operable to: receive a resource placement request from a client, comprising a plurality of resource pair specifications, wherein each resource pair specification indicates (a) a first desired capability of a first resource to be identified from among the plurality of resources (b) a second desired capability of a second resource to be identified from among the plurality of resources and (c) a desired network traffic rate to be supported between the first and second resources of the resource pair; identify, in accordance with each resource pair specification of the plurality of resource pair specifications, a respective first and second resource of the provider network (a) matching the first and second desired capabilities indicated by the resource pair specification and (b) linkable by a network path configured to support the desired network traffic rate indicated by the resource pair specification; provide a plan to the client of an acquisition of the identified resources on behalf of the client; and in response to a plan implementation request from the client, acquire the identified resources on behalf of the client.