Modify open source android applications for secure instant messaging, VoIP, and email

I have three open source Android applications that do the following: 1. Jabber instant messaging based on XMPP protocol (with secure OTR encryption support) 2. SIP VoIP calling based on SIP (with SRTP/ZRTP for call media encryption support) 3. Email (with OpenPGP based email encryption support) I would like to change for each of the apps above: 1) the look and feel (aesthetic and visual elements including UI/UX) and make it conform to my company's branding and design philosophy. 2) improve performance and debug any issues/incompatibilities in the open source versions 3) optimize for use on different OEM hardware (e.g. Nexus, Samsung, HTC), different physical screen sizes and resolutions, and on both Tablets and phones In next phase I would also like to take the iOS versions of these open source applications and change them in a similar way as described in the context of the Android apps above. Please submit your proposal including fixed cost and times for ONLY the Android apps re-engineering. We can do the iOS apps in Phase two of the project. Also provide your email and Skype contact details so we can discuss more details. Sachin