The MR is a beautiful helmet, though they have, historically, had delivery and timing issues. Also, the foam padding makes them fog within three minutes in moderate weather (as my step brother told me about his, and thusly, he ripped it all out).
There are a few fan-made helmets that are nice, but there are availability issues on some, size/proportion accuracy issues on most, and modification issues on others.
So, clone helmets are kind of a challenge these days. Safest bet is getting a MR, and gutting it of it's foam (surgery), installing fans and a microphone... the only thing is they are pricey... but more are showing up on ebay. If you have the cash... go for it.
As far as fan-made... it sure would be great if there was a consistent, courteous, expeditious... and accurate source of clone helmets out there. Especially ones that don't cost too much or require surgery to wear. These are typically less expensive... but they are becoming harder to get as of late.
Oh well. :unsure Good luck on your quest.
John
By the way, here is my fan-made...