Bad news 
I was too careless and lost all my mined spreadcoins. I contacted several data recovery companies and most probably it will be impossible to recover my wallet. Without these spreadcoins I will have no incentive to futher develop and support SpreadCoin.

Sorry for wasting your time with this cryptocurrency

I think I found a way to recover my spreadcoins but you may not like it.

As I lost my wallet.dat I don't know exactly what blocks I mined and exactly how many coins I had.
I can approximately determine block before which my lost coins are situated. Everyone who have mined coins before this block will send them to him/herself (this can be made automatic). This will mean that this coins are not mine. Then, using some hack and releasing a new client I can send myself amount of the rest coins (or maybe less, say 80%).

This rasises two concerns:
1. What if someone will forgot to send coins to him/herself? These coins will still be spendable so he/she will not lost them. This raises the second concern:
2. What if I am a scammer and want just to double my coins, keeping old ones and getting new ones? The only way to prevent this that I see is to limit the percentage of presumably lost coins that can be spend but this is not trivial.

What do you think about such a plan? Is it acceptable in you opinion?

P.S. This way there is no need for anyone to donate coins to me.