now, after updating to Cubase 7.0.6, I cannot reproduce the problem anymore.
My Trial of Open Desk expired, but I now own the compressors and the EQ of the Yamaha Vintage Collection. With these Plug-Ins, I did experience the crashes consistently as soon as I would try to edit any Parameter. Now, no crashes anymore.
I am running Cubase 64 bit version, and I am using the 64 bit VST3 version of the plug-ins.
SW: C 7.5.30 /64 & Wavelab 8 on W7/64 & W8/64
HW: 2 x Dell Precision T5500 Xeon 12-core workstations
Audio: 4 x rme HDSPe / Multiface II, 3 x Octamic II
Surface: 3 x Avid MC Mix, 1 x MC Transport
Plugins: Audioease, Lexicon, Neve Portico, Yamaha Vintage, SlateDigital, Izotope