sip carrier switch - repost

hi I am looking to get a carrier switch built with sip i also require a billing platform. long term also looking to have a available a carrier switch. I own a company in Ireland which currently supports a large instal base of legacy PBX. I wish to deploy a carrier switch to a data centre to enable me to offer sip voice services over sip interconnects. as a longer term I which to develop a Hosted switch with an easy to use web interface to enable be to offer small hosted systems to multi tenant.