I love my Spesh Propero lid - light, comfy etc etc, but the visor is, well, rubbish. It's narrow and high, so not great at keeping low sun or (today) rain out of my eyes (i'm sure it's great in the blazing California sunshine...)
Sooo, do aftermarket visors exist?
You mean the peak?
There are some people who make aftermarket peaks but they tend to be more for full face helmets. Troy Lee do a range.
Might be worth looking at other models of helmet that have a peak more like the one you're after and see if you can buy a spare one of them and bodge a fitting.
use your existing helmet in conjunction with this:
[img] 
[/img]
Sorry, yes, the peak.
I've got a scar across my forehead where I crashed, hit my head and the peak slipped off the front of my Met helmet and created 2" long gash. and that was designed to fit - I'd be very careful about bodging something on.
You used to be able to buy a million differnt styles of MX helmet peaks/visors back in the late 70s 80s but that was a long way back, when all the manufacturers used a pretty standard 3 snap stud fitting. I dont think any maker sticks to that anymore.
In answer, no I have not seen any multi fit peaks..