Needing Advice

I have these twin archways in my very formal dining room:
Though they aren't the best arches I've ever seen, I still think they should be highlighted better.

Having someone come in and make custom trim is way to expensive.

I know that I can make decorative accents for them, but my only problem is the curves.

How on earth do you make your own arch trim?!

Any crafty advice would be much appreciated. I'm usually good at coming up with awesome ideas, but this is leaving me stumped.

Any and all suggestions are very VERY welcome!

Now that we got that done, I carved pumpkins with the munchkins last night!

From left to right: Will's scary pumpkin that he got to carve all by himself (1st year!), John's very happy pumpkin that he drew and gutted, and Hailey's random drawing that I managed to squeeze out of her (such a cranky girl....)

Need any more proof that she was crazy tired? Haha.

Alright, I've been really chugging along on this big reveal, so it should be done in the next few days. I'm almost done with the staircase hallway as well. Here's a peek at the BIG REVEAL:

Gorgeous detail!