I've been "researching" (just making up whatever I need to)
in order to create....
a complete cloaking system:
Superior Invis (including the masking of heat signature, for those futureworlds where everyone has infrared goggle eyes).
Stealth Mage Emanation Filter (shuts down things like Arcane Sight & Detect Good/Evil/Magic,; bypassing Glyphs or modern surveillance like laser tripwires & motion detectors)
Epic Mindblank (in the form of permanent body rune tattoos) to wipe out psi detection methods.
Quickly Forgotten (mind-effecting + minor reality alteration sweep) -- to limit the damage when you are observed by mistake or when you must allow yourself to be observed for some reason. This lets you tour enemy territory and interact with checkpoint guards & shopkeepers normally, but then minutes later all memory of you is wiped from their minds (and from their cameras, log books, etc.)
Pass Without Trace / Woodland Stride (vs. mundane Spot attempts)
To get around the problem of self-imposed Silence that comes with Superior Invisibility:
Spell Like Abilities can manage this, so try harder to have some of those SLA's. Also, to reclaim regular spellcasting...
Silent Caster Feat (which only provides 1 (?) emergency spell I guess, unless you could apply the feat a bunch of times or research a version of it which converted your entire spell list to silent casting);
Rune-Casting of your spells (replace verbal component with glittery air-drawn Rune pattern, like with Symbols)