I don't think this looks bad at all. I will say, and take this with a grain of salt, those LEDs might be a tad much. The way my windows are in my reptile room allow me to skip enclosure lighting. My crew gets just natural light all day so like I said, take that with a grain of salt you may be fine.
Just remember that if you get a hatchling, it's going to be tiny. Like I was surpised how small mine was when I brought him home and even now he's barely as big around as my index finger. I know you already have a plan to fill in all those little spaces, but just be sure to double check them because these guys are small and stupid strong for their size. The only other thing I would suggest if you're going to try to put one directly into this, is clutter it up really really well so it'll feel secure. I started my guy off in a 10 gallon and he did really well, but have since moved him into a 20 gallon long and I don't see him outgrowing it anytime soon. To be honest though, I like your set up and might look into building one myself when the time comes for an upgrade.