A quick Google search gave two companies selling lowering links for the XTR,
lustracing.co.uk and lowering links.com. But the latter is not very cheap.

After searching this forum I found all the dimensions for lowering links for my XTZ and had a friend made me some to drop the bike 1".
On my bike I didn't have to shorten the side stand, although it was standing more upright.

For what it's worth, on the XTZ, lengthening the links from standard 125mm hole centers to 133mm would give 1" drop and 140mm gives 2" drop.
The ratio is 1:3.4

Hopefully someone can chip in to advise how the XTR differs if any.

__________________
2014 XT660Z - Barrett pipe, DNA stage1.5, Barkbuster hand guards and handlebars, Pivot pegs, Teknik suspension, Guard-it engine protector combo, B&B rear rack, Trax topbox.