Well, I'm not looking to start an argument either, and honestly the suggestions I made, are because I'm not familiar with your level, nor do I know how much time you have. As for the Mendelssohn, yes I'm familiar, but I'm familiar with lots of other things as well, it's just I have a soft spot for the songs without words, not even because I play all of them. Also, the time limit kind of puts a cap on rep you could do. I don't know how long the stravinsky sonata is, as I wasn't aware he wrote one either.
But since I'm now aware of what exactly you can play, maybe something from Petrushka? I still think you should pair something lyrical with it though. In a lot of ways, the Casella Toccata has a mix of virtuosity, and is also coloristic and lyrical, if you're familiar with the work. The recording on YouTube is crap, so I wouldn't let that color your view of the piece, but it would at least give you an idea of what the piece is like.
From a listeners standpoint, I'd be reticent about sitting through too many contemporary works. That's why I'm suggesting things more in a romantic vein, they're usually easier listening for audiences. If you're looking for something difficult, one of the transcendental etudes? Feux Follet? Mazeppa? etc.... From what I've heard of what you've played (now) those should be adequate.
You didn't cause me any trouble, but sometimes it bothers me when people discount pieces for simply being easier than what they're capable of. But since you're so adamant about the difficulty of rep, I'm going to assume that this recital is either for school, or for other musicians, in which case, I understand why it would be important to choose an appropriately difficult work.
As for my background in repertoire, I'm really familiar with a lot of things, not just the Songs Without Words... Lol. In fact, I only play two of the Songs Without Words. That duel was an excuse to learn more, and give myself a deadline for some. But anyways, I'm simply a little partial because someone special to me plays quite a few of them, and quite well.
If you do attempt the Casella (and no, I didn't suggest it because I've played it, I haven't) toccata, be careful. I don't think it will fight with you too much technically, but it's much less bombastic than you might think just by reading through it. It's not your typical toccata. Also, It's required rep for the Busoni comp, so uh maybe it'll be useful later.