When 4E was announced, the market for 3.5 products died almost immediately as distributors and retailers no longer wanted products for an "obsolete" game. At that time, Necromancer has three adventures ready for printing but had to cancel them. These adventures are now collecting dust as Necromancer waits for an acceptable revision of the GSL.
Would it be possible for Paizo to release these "lost" Necromancer adventures through the "Game Mastery" line and turn the line into something similar to what White Wolf did with "Sword & Sorcery Studios"?
The Game Mastery line presently consists of "neutral" accessories. Paizo could publish Necromancer's 3.5 adventures under a "re-created" Game Mastery Adventures line. This way, Necromancer could continue to produce 3.x material but under Paizo's label which distributors and retailers would recognize and want. Since these adventures would be Game Mastery products rather than Pathfinder products, a license wouldn't be needed (beyond the OGL) and the adventures wouldn't be linked to the Pathfinder setting and thus remain setting neutral, like all of NG's adventures.
Currently, GameMastery products seem to be few and far between. I don't see why Paizo couldn't slip one of Necromancer's 3.5 adventure into the production/release schedule every once in a while. Paizo already intends to do Necromancer Games' 4E products which, in accordance with the GSL, will require an entirely new product line to be created. Why not just use an existing product line to make new Necromancer 3E products as well?
Of course, its probably not that simple and there's probably more involved than I'm aware of but it's just sorta my own personal theory/thought/idea of how Necromancer could get out of "idle" and back into action.