Help to create a mobile version of WP site ..

I need to develop a Custom WP theme for desktop with a custom designed version of the same WP site for mobiles.

So users accessing it will be automatically directed to mobile version with ability to switch back to desktop version.

I want to know is there any plugin that will allow me to custom style & code the mobile version theme of the site as well as achieve this function ?

If not, how best can i achieve this ?

Ive seen this http://wordpress.org/extend/plugins/wptouch/ but doesnt look to allow me create a custom styled mobile version theme of site.

Also had a look at http://wordpress.org/extend/plugins/wp-mobile-detector/
This too am not sure if it achieves what i wan.

Does anybody out here is experienced with this & can let me know the right way to go ahead with ?

NOTe- Client doesnt want responsive solution.So thats not a option over here.