Yukon's are sold through Randy's Ring & Pinion.
I believe Alloy has a lifetime warranty though.
As for the warranty itself, yeah, it doesn't help you get back home but it does get you back on the road without having to shell out more money.
If I was running a D35, I'd go with aftermarket HD shafts and keep the stockers for spares.
Now one of the advantages of the Scout D44 is that the pumpkin is offcenter a bit. This allows for the axle shafts to be equal length so you only have to carry one shaft for either side. Most other axles have a left and a right side shaft. Although if you're in a pinch, I think my might be able to use a short shaft on the long side.