I think you have an interesting direction. I think there'll be plenty of opportunities for looping holes, tho. Like if a corporation gives money, it would HAVE to disclose it on its own balance sheet or how are stockholders sposed to know where the money's going? Plus if Donor X goes to a $10,000/plate dinner, then you'd have to know they donated $10K, right?
And how does this affect my company running pro-Such-n-So advertisements? Would you inhibit displays of "Sponsored by...." at the end of each commercial?
You're headed in a good direction, but there's some glitches.
It isn't a bad idea but I think it isn't doable. Also, it does not address the problem of repressing political speech. Organizations will still want to speak out and speaking out takes money. There is no way around that.