Hmmm...might be a bit far, but 31 from Mt Pleasant to Donegal has a good 3-mile climb at 8-10%. 'Good', in this context, meaning wide shoulders and no shade whatsoever, so you won't have to worry about traffic when you fall over from heatstroke.
Classic multi-milers to the SE, not within 50 miles, but really worthwhile:
Head over Kentuck Knob from Connellsville to Ohiopyle, via Furnace Hill Rd. Really pretty 6-mile steady climb at 4-15%, with about 1200' of elevation gain, followed by some exciting V-shaped valleys and a mildly scary descent to Ohiopyle. Return to Connellsville via trail, as you do NOT want to try to climb back out of Ohiopyle that way.
From Ohiopyle, climb Sugarloaf to Confluence via Sugarloaf Rd. 5-6 miles at 5-15%, 1500' of gain, then drop into Confluence. You can get back to Ohiopyle by turning around and climbing Sugarloaf again (you sick masochist you), or just grab the trail.
From Confluence, you've got the Mt Davis climb. Head down 523 to Listonburg, then left on Mt Davis Rd. 10 miles, 1500' of climbing, to top out at the highest point in PA. Yet again, turn around and climb the mountain again, or catch the trail in Meyersdale.