Anyone try the Boom!™ Audio N01 Half Helmet yet?

 

That's basically a SENA Calvary Helmet branded HD, that might help your search.

https://www.sena.com/product/cavalry

I tried one on at America last week, I was impressed how loud the speakers were! Unsure if you'll get strereo if paired with the WHIM, but a call to SENA would confirm that.

 

Here's a review of the SENA Cavalry helmet by Ryan Urlacher on his "Law Abiding Biker" channel (this is one of his free vids):



He's clearly over the top, but he does get pretty in depth with the review. As for the WHIM compatibility, I'm going to go out on a limb and ASSUME (you know what happens with that though) that it WOULD have full stereo functionality, because the Boom! gear that SENA creates is specifically programmed with the correct (and enhanced) Codecs and firmware to work fully. NON-Boom! SENA gear doesn't have the 'flag' in the firmware that tells the WHIM that the device is a Boom!-spec device, so it limits the functionality to mono audio and minimizes the feature-set.

 

I've used a Sena Cavalry helmet for over a year now. I love it for in and around town. When you make more than a couple stops, it keeps from having to plug and unplug every thirty seconds.

Be aware, over about 45 the mic is hit and miss at best. Most of the time people say there's too much wind noise and I'll wait until I'm off the interstate to call back.