I'm actually casually looking for a higher quality replacement myself, not particularly for any other reason than the OEM one feels under cheap, and rattles. I'm waiting for the day the headlight just falls out.
I noticed one by EMGO (I'll try to remember to post a link later), but it's so inexpensive I wonder if it's not just as bad. An I don't know dimensions yet (not 100% sure that it fits or that it would suit your purpose any better).
I half wonder if there's an OEM take off from something that might work better?
I assume you've not found anything yet?