Ah, this is very interesting! This April I went to
Dhammacari, a hardcore Mahasi centre in Germany, where they make you stay awake for 72 hours at the end of a two week retreat. On the penultimate day, you are told to make this resolution before you sit:
Within this 60 minutes sitting period, may the Phenomena of Arising and Ceasing appear as often as possible.
In other words, may I experience a ton of fruitions. This worked well for me: I had loads, all very clear. On the last day, we were given a harder task, expressed in this resolution:
Within this hour, may I experience the State of Meditation without consciousness of outside phenomena for 5 minutes
If we were successful - i.e. if we felt that time was somehow "missing" when the bell went at the end of the sit, we could change the resolution to 10, 15, 20, 25, 30 and 60 mins, incrementally. I didn't manage this at all, but it sounds a lot like what you might call extended fruitions.