Not many people being helpful here. I've developed plugins before so I can give you some advice :)
It would be helpful if you could specify what sort of custom plugin work you're looking for - and always do plenty of research to see if the plugin already exists. The most common features are always out there somewhere.
Secondly, what is your budget? Most developers will not be willing to develop a custom plugin from scratch for free - programming plugins is hard work and they don't appear magically.
The best thing to do is go to Bukkit/Spigot plugin forums and request the plugin you'd like made in their requests threads. Developers will not come messaging you if you don't state what you want and what you're willing to pay. The difficulty of your request will also determine the skills a developer will need to help you.
Hope this helps.