I can direct you to those suppliers who are at the pinnacle of their craft.
Kilt hose See my links page for suppliers of custom-made kilt hose. I no longer stock machine-made hose as I no longer have a high-quality source.
Garter-knots I can make either ‘plain’ or tartan (to match your kilt) garter-knots in a variety of styles.
Sporrans `Bespoke`, custom` and ex stock. L&M Highland Outfitters have the highest standard of workmanship that I have ever seen: http://www.landmhighland.com/
I am working on some of my own designs, which I will post here when they are in production.