I have noticed that but I had no problems finding Rust around here which is strange and it seems quite common in the USA too from the people I have chatted to there. Maybe some have the colour wrong, I don't know
My favourites are the cream based hamsters - Sable and Mink in particular, and especially in long hair, although I also love seeing the effects of Yellow on different colours (tortishell) and the prettiness of the Dominant Spot pattern on most colours but especially the Selfs. Agouti means the hamster has three distinct shades of colour along each hair, dark cheek flashes and crescents, also known as the "wild type". Self fur is the same colour from roots to ends. Some Self hamsters, such as Minks, Sables and Yellow Blacks, have hair with two bands, but this shouldn't be confused with Agouti. It is essentially Self fur with tipping.