Mobile plugin that redirects (302) mobile users?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  W.E. Jonk: probably not an option since you already implemented a m-dot site. But you could use dynamical HTML with the vary HTTP header. With that you keep the URL the same and only the HTML changes to serve a mobile optimized page. Like with any user-agent sniffing it is pretty much an arms-race.
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  Tony McCreath: I may be able to do that via .htaccess rewrites. I like the idea. Down side it does force what a person sees, but so does basic responsive.
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  Edwin Jonk: you can set it up so that you only "force" the mobile version once and once the desktop version is chosen you serve that version the next time first. Or vice versa. If you serve the desktop version and they go to the mobile version the next time you serve the mobile version first. You can do those things with cookies. But this is similar to m-dot approach. The difference between m-dot and dynamic HTML is that the URL doesn`t change and thereby any incoming links aren`t really a problem. However with both approaches you need to sniff the UA and that will make it quite time-consuming....
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  Justin Y: Why not use mobile detection and add redirects based on their device in the head section? Implement some php if statements to redirect users based on their browser if you`re using php. I think responsive design would have been the better choice and then add htaccess redirects for the existing mobile links. Then you would gain all the traffic to a single url.