We've heard that Apple will be focusing on its Mac lines this WWDC, and now another rumor from 9to5 Mac claims that one of the updates will be to the oft-neglected Mac Pro. Their sources claim to have part numbers for three varieties of the desktop: two standard editions and one that supports OS X Server. Pricing will apparently be similar to current versions, and though 9to5 Mac has previously heard some interesting things about a rackable Mac Pro server, we don't really know what features Apple might add besides (likely) Thunderbolt ports and updated specs. It would be the first revamp to the line in two years.
Both 9to5 and MacRumors have also reported that Apple is pulling the Mac Pro from stores in advance of WWDC. Nearly all of roughly 100 stores that MacRumors surveyed had no standard entry-level models in stock; they were reported to be coming back either June 8th to 9th or June 12th to 13th (the WWDC keynote takes place June 11th.) If Apple is indeed updating the Mac Pro and the previous rumor about four Mac lines being revamped is correct, that means that the Mac Mini will be left out this time around.