Hello everybody. I know I'm late to the party but I support this, and as far as I'm concerned it's more likely than it seems with his absence from spirits and boss fights despite his significance in Brawl. I thought it was very strange that there wasn't a trace of Porky as himself in Smash U. To me that just screams "He's coming, wait for it!"
Not sure if this has been mentioned yet (if it has been, my apologies. I'm new here...) but there are only 4 characters with a weight value of "120" or higher vs a total of 12 characters with a weight value or "80" or lower (these values are 20+/- compared to an average value of 100- Mario's value when the weight value system was first used).
I imagine if they'd add Porky in mech he might fit into the "higher than 120" category, which would add to the underrepresented heavyweight class a bit. In general, it seems like Smash U has been very kind toward heavyweight characters in comparison to previous smash entries. Bowser, DK, and Ganondorf all look very promising for example. I'd love to see another heavy added to the cast.
Also, Sakurai mentioned in an interview that he wanted the DLC characters to be unique fighters. I imagine that's one of the reasons they added Joker to the series - he will probably be a unique fighter utilizing the persona summoning and such. A mech character like Porky could also be very different compared to the cast we currently have. If they do add Porky, I'm excited to see what they make his kit.