This kills it as a viable alternative to DocuSign. The point of Docusign is that it is an independent third party that maintains custody of the signed contract and proof of acceptance (i.e., digital signatures) by all parties to the contract.

A self-hosted digital signature system isn't worth anything in court; the other parties will simply reject the authenticity of any data held within it and the amount you'd have to spend to get that data into evidence would probably pay for several centuries of DocuSign's enterprise edition.

That being said, the cloud-hosted option seems viable as a competitor for Docusign if it's offered by you/your organization as a service, and could provide financial support for continued development.