@imtrobin - take a look at Alfresco
for a Sharepoint alternative you can host yourself.
I don't know how well it may meet your specific needs. And I don't have much experience with Alfresco beyond setting up a small test environment and playing with it for a few weeks a while ago. But I do recall being very impressed with how well it stacked up against Sharepoint in a feature by feature comparison. It's pretty much the acknowledged "worthy competitor" to Microsoft's collaboration offerings.
Alfresco is a FOSS product so there's a free unsupported community edition you can download if you want to give it a try. Just commandeer a spare PC, or set up a virtual machine, load up your software and have at it. Only some hands-on experience will allow you to accurately determine if Alfresco might work for you.
Fortunately, it will only cost you your time to check it out.