Are there any non official twitter apps that shorten with t.co or is this not even possible?
All applications that post tweets to Twitter will have links wrapped in t.co.
Sorry, I should have explained better. I mean to type in a full URL via a 3rd party app and have it directly converted to t.co. I can’t do that via HootSuite, for example. My URL gets converted to ht.ly Hootsuite then it gets converted to t.co.