The repo is public, and there are other developers on these forums,
We have a thread here, where you could make a request, which any developer could pick up, or if that fails you could go more general.
As a general rule : you are going to want to assume about $150 USD per hour, plus the cost of the device. Timewise I would expect 1 day to understand the code base and adapt to it, 1 day to test and then obviously time to code the device. $3000 - $6000 USD, would a decent incentive for as contractor.
Someone very familiar with zigbee on Homey could do it faster, but they will likely expect a higher rate. Keeping in mind that ted is ‘the guru’, for these devices.
I hope you find this useful and it helps you put a proposal together to find a developer.