No, IO recipes cap at level 50. However, there was a bug in the market window that let you place a bid on them for a bit, and you can still see these if you can find one that has a bid on it, and even place a bid for it, even though you will likely never, ever, ever get one.
Let me never fall into the vulgar mistake of dreaming that I am persecuted whenever I am contradicted.
~Ralph Waldo Emerson
"I was just the one with the most unsolicited sombrero." - Traegus
I sure hope I don't. 
As an aside, have you ever set the CH interface to display only bids on level 53 recipes? Despite specific advisement not to do so, there is a lot of inf. stored on those.
There are no words for what this community, and the friends I have made here mean to me. Please know that I care for all of you, yes, even you. If you Twitter, I'm MrThan. If you're Unleashed, I'm dumps. I'll try and get registered on the Titan Forums as well. Peace, and thanks for the best nine years anyone could ever ask for.
Been gone awhile, and I'm wondering: are there level 53 recipes drops (really any +50 recipes drops)? I do not see them for sale anymore, nor have I gotten one while playing +3 +3 no AV, or +3 +3 AV.