There have been several threads about this issue, both here and on other boards.

Most major manufacturers stock is gone and the deliveries from Asia are coming much slower than typically expected. You are pretty much going to have to start calling around to any distributor that you do business with to try and find your parts, or get comfortable with sending your customers to Best Buy or online to get them. The only products that have been consistently available were the higher-end stuff (Anthem, Arcam, Audiocontrol, etc), but even those are starting to get harder to get as everyone is being forced to spend up just to get something.