It's possible, and relatively simple give the skill and kit, to skim the difference between the cassette widths from the back of an 11 speed road cassette on a lathe. I've done it a couple of times, and it only took about 5 minutes.
Obviously depends on having access to a lathe or someone with...
Re:
I've a load of Michelin DH tyres, comp 16 2.5"&2.2&, comp 24 25."&2.2", mud 3 and a trimmed mud 2.
Also got an E13 bashguard, and a few parts from an original MRP chainguide.
Pretty sure I've a goldtec DH chainring knocking about too.