Marc convinced me that he knows what he's talking about when it comes to fuses so the intent of my original question was to ask him about "aircraft grade" fuse holders since I didn't really find them at the usual places... I thought there might not be a specific aircraft grade product in the way of an inline fuse holder so I was hoping to be referred to a better quality fuse holder.
The ones I pointed to are completely adequate for aircraft. While the admonition to use Tefzel insulated wire rather than PVC insulated wire is an excellent general recommendation (I ONLY use Tefzel wire for wiring when I have a choice and the opportunity, due to the higher temperature rating and the far lower poisonous outgassing in case of fire), it's not always possible, and there are probably a few feet of PVC insulated wire in my plane.
Recall that there's also a crapload of plastic in every plane that will outgas Cthulhu knows what if it ever is exposed to flames, and you're just not going to get rid of everything that's flammable - we do the best we can.
Now, We can minimize the PVC exposure by cutting the leads on the inline ATO fuseholders short and splicing them to Tefzel wire within an inch or two of the holder itself, but I still recommend using the fuse buses that B&C (and Stein - they sell exactly the same fuse buses that B&C does) sells.
Stein also sells resettable ATO compatible CBs (they call them resettable fuses), if you'd rather use expensive stuff for some reason - they're taller, but could be put in a bus on the panel so as to mimic the accessibility of CBs if you wanted the ability to allow the plane to set itself on fire more than once. Not my preference, but to each his own. Stein's web page has all of this in the shopping section, under circuit protection.
As others have said, there's no such thing as "Aircraft Grade", any more than there's any such thing as "Man Rated" for spaceships - it means whatever the MFG wants it to mean. While it is certainly the case that there are a lot of OWTs and unsupported opinions in aviation (and, in fact, in any technology, but moreso in aviation due to the life and death nature of mistakes, hence a resistance to new stuff), MOST of the recommendations you'll hear from folks that actually know their stuff (Bob Nuckolls, Mike Busch, etc.) will include new knowledge and learnings and will be good advice, and most of the time, when someone like that tells you "don't do this: it's a bad idea, AND HERE'S WHY", you should listen to them. Same with "do this - it's a good idea, AND HERE'S WHY". The operative part here is "AND HERE'S WHY" - it's never "experts are stuck in the past and are only grinding their own axes".
And the recommendation to use CBs for "critical aircraft systems" is exactly backwards - one should use the most reliable device for the most critical circuits. CBs do not fit that bill.
