curious what InSign would look like.

InSign, will be more of a website for contract signing, where the signature will be a transaction on the block chain. Just like a contract involves multiple parties, the contract sender will be able to upload the contract, which will then be emailed to the signer, who will review the contract and send a unique INT amount to a unique address instructed in the email. This transaction will indicate that the contract has been signed.
What's to stop someone else from finding out the INT amount and sending it to the specified address, which in effect will be like forging a signature?
The INT amount and the address will be sent only through the email, thus ensuring that only the signer , and the website are aware of the amount.
In that case, there's always the risk of a hack or email phishing or any number of exploits that can be used to "steal" the email information.
I'd suggest to add in a sort of verification from the receiving end as well (such as having the receiver submit an address from which he will send the required INT). This way, even if a 3rd party gets hold of the contract info, the theft is irrelevant because he/she does not have access to the receiver's wallet aka "sending address".
Maybe adding 2FA would be a smart step.