on the emule-project forums they are constantly throwing around ideas to improve the reward system in emule "how should we reward uploaders?" "should we reward uploaders?" "my credit system is fairer and faster" "my mod spreads rare files better"
its all being.... and has already been.... discussed millions of times,
I'm sure when the dev team at emule deicide on what's best, it will be implemented into amule there time after.
but for the moment, I'd stick to 'wuischke' suggestion above.
i.e.
Run and leave, come back in a couple of days and everything will be done, leave for a couple of more days to give back.
easy.