Don't really need to worry about overrevving these engines - they have a rev limiter at something like 8100 rpm. But I can't imagine getting a bike that long, low, and heavy to wheelie - usually the bikes that do wheelies are light, put the weight fairly high, and have a short wheelbase, I think. Seems like a really bad idea to me.
I've accidentally wheelied my scooter before - feather the clutch "just right" on a light bike at high rpms and that front wheel will come right up. But even under extremely heavy acceleration I've felt no tendency at all in the Bonneville to raise the front wheel. I'd think it would be even less likely on the speedy.
2005 Aegean Blue Bonneville - Intiminators and Thruxton preload adjusters up front, Ikon 7613s in the back, otherwise stock
2012 Azzurro Fiat 500 Sport