Develop a Minecraft Forge 1.7.10 server-side mod (with optional client mod)

We are running a Minecraft 1.7.10 server on KCauldron (Bukkit + Forge). This means fairly old version while also using a platform that does not have perfect compatibility. We are aware this may make the work more difficult. But we need someone to code a mod for us. The mod we would like to have, would be very similar to existing plugin ([login to view URL]) Basically it will bring the concept of Grand Exchange from the original game (RuneScape) into Minecraft. If you aren't familiar with this, I can maybe describe it better in discussions. But the linked plugin should also give some idea. Now, to the reason we want a mod instead. Basically the mod could work nearly identically to the plugin, except there should be the option to install client mod in your own client. Our server would then detect the client mod, and offer different interface that is more comfortable to use (Text search for items, text input for item amounts and prices). The layout in modded interface should be as close to the one original one as possible. Screenshot of that will be attached. The work would include making sure the mod works flawlessly in our current server environment, including both KCauldron, already installed mods and plugins. I have not used this service before, so I wouldn't know if there is some way to communicate, at least before posting the project. But I can be contacted via Discord at Shinare#6951.