The question has come up before with no really good answer. I think the problem is that the further you're willing to go, the better the hills you can find.
There's some fair hills right close to White Rock Lake, though my normal route around the lake misses them all.
There's a pretty good ridge that you cross on I-20 down south of Dallas, and that ridge continues south, but I haven't biked down there, either.
One of the charity rides has what's supposed to be some good hills up around Trenton- the Three Sisters or something like that. I don't think I've ridden over them, or if so, they weren't impressive.
I've seen a post where somebody talked about some steep hills on the west side of Fort Worth, if that's not too far.
The Beauty and the Beast route has a good hill near Mt. Selmon.
Our latest brevet had a good downhill north of St. Jo, even had the "Steep hill" sign for trucks. I think the Mt. Selmon hill might also.
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