Apple looks set to refresh its server lineup with news that supplies for its existing products are constrained. 9to5Mac is reporting that retailers are struggling to get new orders for both the Mac mini server as well as the Mac Pro server, with no new shipment date being supplied. If true, June is shaping up as a bigger than usual month for new Macs. There is also an expected Macbook Air refresh enroute, which will likely launch at the same time or just after the launch of Mac OS X Lion.