*Note, I'm not trying to recommend this, but I am curious if it can be done.
In this question, Steve V.'s answer made me wonder about this:
One time during my commercial training, my instructor and I received an "area clearance" over downtown Nashville for simulated aerial photography, which allowed us to circle over downtown with visual reference within class C airspace as we wished with no defined route.
In the above case, we were not on an IFR flight plan, nor were we above the IMC floor.
Is it possible to get an IFR clearance for an area as VFR-On-Top, without having to file a routed flight plan with fixes, effectively allowing an instructor and a student to practice with their own spontaneous navigation choices in VMC at an altitude above IMC conditions?
Same as above, but foregoing the VFR-on-top and accomplishing it purely as IFR.
File two IFR flight plans, cancel the first one once above clouds in VMC, do your thing, and then receive the next IFR flight plan clearance to shoot the approach back down.
Are any of those options?