AppleInsider reports that Apple issued a note to its retail stores yesterday stating that no further orders for a number of the company's desktop computers would be accepted, suggesting that supplies of the machines are running dry ahead of product updates. The note refers to all iMac configurations and the low-end Mac mini as being affected.For example, Apple Retail on Monday issued an advisory to its stateside brick-and-mortar shops in which it noted that further orders for many of its existi