The tileset is as finished as it is likely to get right now, so don't expect Supindahood to make any updates, possibly ever, though I haven't spoken to him about this for a long while. That said, there is more Firebird graphics coming! They might just not take the form of an actual update to the tileset. Then again who knows, maybe I can convince Supindahood to make an update with the new graphics that'll come from the project I'm working on with the tileset. I would do it myself but trust me, none of you want a Firebird compiled by me; it would be a disorderly mess.
Speaking of, I'm actually sitting on a rather large graphic for Firebird right now, and the only reason I haven't submitted it yet is because I want to have a nice screen to go with it. Not that you'd need a screen for a tile submission but it's a little big and hard to use given screen space limitations so it couldn't hurt to have an example shot. It's just a single building though, so it probably isn't going to help you all that much right now unless you are in dire need of a gigantic temple of time exterior.