This is also gonna be a shameless plug, but I think Resounder is just what you're looking for. You can have unlimited soundboards and each sound you record is stored in a 'Sound Library' that you can use to share sounds between soundboards. We are also releasing an update within the next few days that allows you to download sounds off the internet and add them to your soundboards. Give it a look (we're on sale right now!) at www.resounderapp.com