I too came here because I wan't to access some large file on a USB drive from my LG WebOS TV, and I use Mac so I can't use NTFS.
But I must clear up some misunderstandings:
exFAT IS NOT STANDARD on most Linux distributions!
Actually it dosen't even have a kernel module (only Fuse userland module) because exFAT is a licensed, close source and closed protocol.
It's not difficult to find this information, just look at wikipedia:
"exFAT (Extended File Allocation Table) is a Microsoft file system introduced in 2006 optimized for flash memory such as USB flash drives and SD cards. It is proprietary and Microsoft owns patents on several elements of its design"
It was meant to replace FAT32 because of the filesize limitations. NTFS was doomed not feasible for small removable devices. But the biggest problem with NTFS is actually that it is closed source and support in other OS'es than windows is either made by:
a. buying and signing an NDA with Microsoft or
b. reversed engineered. Which is the solution Linux and Mac has chosen, and the reason Mac (and earlier Linux) defaulted to mount readonly. They didn't want to risk destroying anything.
So while I do agree with Microsoft that we need a new filesystem. I don't think a proprietary filesystem is the solution, for storage that is meant to be used in a lot of different devices based on different OS'es.
Could it be a solution to split the MKV's to multipart? I haven't tried but maybe WebOS will play them seamlessly.