SIP VOIP PROXY (LCR)

We need a perfect clone of a sip proxy like sipsnip .com for our users The users have to register on an own sip proxy with their sip phone. This sip proxy itself stays connected to several other sip services. So the new sip proxy can route incoming calls from a sip service provider to the sip phone of the end unser. For outgoing calls the user can decide over which sip service he is calling. This can be arranged through a prefix. So it must be also possible to do some kind of least coast routing for sip telephony. We also need an html page where the user can change the data itself. If you need any further information - please let me know. Hope that we made the description clear enough. Please ask - if you didn't understand what we meant. Thanks in advance for your bidding.