Just my

. . . Since you did ask for input about this situation . . .
My first thought is . . .What are the ECF policies & procedures concerning contest?
Next, since I do not know them, I would think to be fair to everyone - Given that you set up the rules that submissions would be for 1 week I think you should stay with that, especially that even with the bumps today not to many other people attempted to enter. So, I would wait till the week is over, then close the contest for submissions.
As for the results, as you stated: "So in the end I will select 3 that I like and let the community decide on the banner sig link" - I would also stay with this since it is what you mentioned you would do.
Well that's just a thought and my opinion. And like I mentioned in my earlier post, I have no problem with what is decided and I definitely agree to go along with majority that participated in the contest.