We need to customized existing open source sip soft phone clients for windows. You can choose between Yate ([url removed, login to view]) and Boghe ([url removed, login to view]). Customizations include customizing the screens and views of the client and changing images etc.
9 freelancers are bidding on average $2367 for this job
I can do it, please check my reviews here on Freelancer.com (http://www.freelancer.com/users/feedback_2115601.html), project completion rate 100%. Also, please check private message I sent you.
We have extensive experience on VOIP client development. Windows/Linux/Symbian/Android/Iphone. We have experience on Pjsip --> Qjsimple based windows SIP client. You will love it.