"sleeves" that go over your hoses will tarnish. They will then look not so good. Now if you went with top quality Stainless Steel hoses, thats another story. It's also alot more $$$.
personally, I replaced most of my vacuum lines with Blue Silicone hose from Stylin Motors. I also replaced my radiator hoses with Blue Anodized Flex-Cool hoses. So, yes I have some blue color going on under the hood. It's my personal preference, as of now.
If thats your show mod idea for now, by all means roll with it. My suggestion is to go with a top quality product, which probably cannot be found on Ebay or Autozone, Pep Boys, etc.