I started with Vinod's patch, but then generalized it a bit.
I added 3 parameters: Min number of entries, max number of entries, and date limit.
The idea is this: Max and Date work in conjunction, to mean "at most x days or y posts, whichever comes first".
Min entries only works if you the date limit also set, to say "well, but if the number of entries within the last x days is less than y (min entries), show y entries".
It's on the tip of oacs-4-6 branch, and will go out in 4.6.4 later this summer.