Is it possible to somehow touch up a prop that has some minor dings on the leading edge of the blades?

I can be made to look like new. Check the internet for a Prop Shop near you.

Here is another in Lansing, IL. You can ship in to them, they also do good work.

http://philspropshop.com/

In my neck of the woods an aluminum prop repair, minor welding and repitched/cupped runs roughly 50% of what a new prop costs.

+1 on Marks in Shelbyville ... Mark isn't a prop repairman .... he is a prop god !!!

that prop will run out better than when new ....

I sent one to mark and got it back about four days later, good as new.  I don't know how he fixed it, and shipped it in that time.