I ordered a deeply discounted Rusk Ceramic Str8 flat iron from eBay. It's got the negative ion technology, 1/2" plates, and a temperature dial.
The Sally's closest to me doesn't carry the miniature Jilbere ceramic flat iron.
I feel rather silly for not having already realized the option of flat ironing the new growth after a rollerset. Here's hoping it helps me stretch out the relaxer better than my blowout attempts did.