Proper Bike Co. has been around for a long time and don't look to be going anywhere. Proper have always been a after market parts company with a few signature frames from Mike Miller and Alex Platt.
Proper also offer Handlebars, Stems, Front Hubs, Cassette Hubs, Spokes, Rims, Complete Wheels, Chain Rings, Grips and Barends. Proper also have some Tees so check them out too.