I maybe old school like other too. Wired speaker sound better to me. run a wire won't take that much longer. If you must go for wireless, why don't you try one of those Sound Projector.
In my opinion, rear speakers are not so important.
Just buy something with normal price will produce similar results.
Either wired ( better ) or wireless, its your choice.
Hope this help
wireless speakers are only for good looking, but just like someone said rear speakers aren't that important, so it's not a big deal for you to go for or not, but
in my suggestion is better for wired.