We have a variety of local sources. We like to touch and feel before we buy. Some sources are nationwide, like Rockler. The rest are local to us in Southern California:
* We bought a large assortment of Jeffrey Alexander brand "Tiffany" knobs and pulls in brushed nickel for our kitchen. I don't like or dislike Jeffrey Alexander knobs and pulls. They feel like good quality to me, but I really do not know if they are up to your quality requirements. Spouse chose them based on looks. They have held up well in our kitchen over four years. We got them at 405 Cabinets in Fountain Valley. They supply pre-made cabinets and a selection of hardware to go with them, but are not a hardware store per se. (Rockler shows Jeffrey Alexander hardware on their website, but I think they may be discontinuing them. You can find them from many other sources.) http://www.405cabinets.com
* Woodward's Ace in Santa Ana (located near Orange/Tustin). They are a special, old school hardware store. We are willing to make the longer drive past other hardware stores to go there.
* New York Hardware in Costa Mesa. They carry a very wide range of high quality products, but they are expensive. Parking is a pain. Back into the parking slots, or you may never get out.
* Muff's Antiques at the "Circle" in Orange. They have knobs, pulls, catches, locks, etc. etc. etc. to replace old, antique ones that you cannot find anywhere else. They are a national treasure, or at least a local one. Once in a while I have a nightmare that the owners may someday retire.
P.S. Related to knobs and pulls and accessibility.
Some people have joint issues. I have seen pull designs that force the hand into unnatural positions. I don't like pulls that force the hand to twist in a certain direction to use them. Some are shaped like upside-down cups, for example. They hurt some people by forcing them to orient their hands into uncomfortable positions to use them. Many pulls force you to flip your hand upside-down with fingers pointed up to open cabinets and drawers. They can hurt to use them.
I prefer open pulls where the hand can grasp them in either direction, with fingers up or down. Those same pulls offer left or right handed use when mounted vertically on doors, too. For people with joint issues, they make a difference.
The same thing is true for door knobs vs. levers.