I've always wanted to do just the inner chamber yellow.
How would I do this properly? 
Me too .... Tempted to lose the vento front in favour of this. Not sure though!!
I'm currently experimenting with a spare lense i have with some yellow glass paint on the inner chamber, just waiting for it to cure and will report back with some results. Alternatively you can get pure yellow H1 bulbs off the lamin-x website but they are like £25 but they will more or less turn the inner chamber yellow.
Well like I said was experimenting and this is the result....
Just some yellow glass paint off ebay (a few quid) and dapped on using a wee bit of sponge and left to cure over night. I was dubious as it just looked like yellow paint when applying it but turned out this lovely transparent golden yellow which should lool awesome. Going to do my headlights like this along with the joey mod later in the week.
