They literally thought they had the deal extended (or some work-around) last Wed/Thur and planned to announce on Friday the 4th. Then it all fell through, and no one at Farsight will say why, which is their right. The Stern SPA stuff is odd based on what I have heard from Stern guys over the years, I knew of tables (that haven't been released) being done ages ago and now they seem to have a green light, but are going to the TPA app.
Regarding the Spike/ Spike 2 capability of the TPA dll, it runs all the recent Stern code, not just Ghostbusters. I'm sure someone here that works on the pinMAME side of things can chime in if they want. But Farsight had the Ghostbusters VPX table removed because it used the Farsight .dll to run, not because of any assets or anything like that.
Interestingly enough, it isn't that difficult to pull assets from the TPA files, but is really time consuming (OS / System hopping) and needs a whole lot done to them before you would want to use them in some "homebrew" creation. Plus, there is the not grey legal issue issue of actual IP theft at that stage.
I guess in VPX terms, it is more of a moral and ethical one as opposed to a technical one in regard to how new of a table do we want to recreate for public release. But I'm sure we'll see some envelope pushing again in the not so distant future.