Thanks for the comments, everyone. They are much appreciated. I put my 5" male convict in this setup today (the one in my avatar). So far, so good. They had a stand-off right away. The turtle looked curious but a little afraid, and my convict stood his ground and flared his gills and did the exaggerated side-to-side swimming like CA cichlids do. After a few seconds they seemed to come to an agreement and are now completely ignoring each other. My con looks fantastic in this setup and is really enjoying the 48x18 footprint I think. Now I can't wait to get the Anubias and crypts planted on Monday. I'm not going to use many, just a few here and there to add some color. Hopefully neither creature will do any damage.
I also ordered a bigger filter (Eheim 2217). The 2213 just isn't cutting it for this tank.
I hope to pick out some danios or guppies, maybe cherry barbs, and start their quarantine soon.
So... I had to remove the con after a few hours. He was grabbing and shaking my turtle, which obviously was not going to be tolerated by me! I wasn't expecting so much aggression, especially considering how big of a tank it is and my con and turtle are about equal in size. Oh well... I added some zebra danios to the tank instead. He likes them much better.