Read the 47th and the 48th post at the Towny Official Thread. @turtledude01 stated this.
I put this in the plugin requests to see if anyone will step up to this. You can talk to them as @turtledude01 said. They may allow it. I put this here to show its an option.
I hope we see someone someone step up to this offer!
Anyone that decided to take over Towny for Sponge, Me and possibly my friend will be willing to help out as much as possible too.
I never really had a close look at Towny to be honest but you might be interested in Polis or Nations 
I am aware of Polis and Nations. I am just saying that the offer is there. @turtledude01 and friend is offering to help the person who takes this offer. Thanks glad you found this. I give this so people using Towny bukkit may have a chance to port to sponge without losing towns.
I give you this offer. Who is willing and responsible to take it?
Wouldn’t the person porting this need to have the express permission from the original Towny devs? Only then you could use the same name/features as them for the plugin.
That was the point of this post. They said that if asked they may grant permission to port to sponge.
I’m going to contact them again tonight and speak to LlmDl hopefully to assure that this is still the case, and to AT LEAST get final approval from them to allow someone to port it.
In order for us to sanction a port of Towny to Sponge, the developer would have to be a good fit:
Most importantly, they’d have to be around on the IRC channel to provide support for their work, Towny has had one of the best support systems for their plugins for many years now and we wouldn’t want that to change. People that join the IRC and stick around almost always get the help they need.
The developer would also have to bring the plugin up to par with the bukkit version and maintain that as the bukkit plugin develops. The database structure could differ as long as there is a converter made to port bukkit databases to the Sponge version.
That developer would also have to show past work, on a level and scope that falls in line with Towny.
And after all that is met, both @ElgarL and I would have to sign off on the port before it’s released to the public.
Yes I made this post to grab the attention of developers that they could maybe do this. The developer has to be a good fit though which you made good points I don’t have to repeat. Glad you found this post.
Anyone wanting to step up to this speak up here and to @LlmDl for consideration. Step up now and be sure to consider his own post here see if you are a good fit. I hope someone steps up!