The project we are working on features a lot of nosing material.  These can be provided by the manufacturer, however we've been making our own for a more custom and flexible installation.  In this project the appearance of the nosing is a big factor in how the finished product will turn out. Of course this comes with a significant installation bill, but for this type of work you need to pay for a really good installer otherwise you risk not only bad workmanship, but wasting costly material as well.