Hello, all:
As an update, the owner of the @InkscapeApp Twitter account posted their 
intent on Twitter to cease using the account and rebrand their product 
before they launched.  The Twitter account has since been terminated, 
but I kept a screen shot (attached).

I emailed Kyle Banks (the registrant for the Inksca.pe and Inkscape.co 
domains) to identify myself as the point of contact, acknowledge the 
termination of the @InkscapeApp Twitter account, and ask him to cease 
and desist use of the Inkscape mark in any other capacity.  Mr. Banks 
replied, acknowledged our ownership of the mark, and said that he would 
take down the Inkscape.co and Inksca.pe domain names and rebrand his 
product.  As of the sending of this email, the domains no longer point 
to an active page.

I'll keep an eye on the Inksca.pe and Inkscape.co domains, but if Mr. 
Banks stays true to to his word, then I think the matter can be 
considered resolved.

Best,
-Tony