There are several cultivars of variegated hydrangeas. They are all selections of H. macrophylla - 'Mariesii Variegata', 'Tricolor', 'Light O'Day', 'Lemon Wave', etc. None of them have what I'd term "speckled" foliage - the variegation is most often seen as bands of color along the leaf margins although these may be irregular in form. Kinda like hostas in how they show most variegation in streaks or bands rather than dotted or speckled.

Regardless, you will have to go to some extraordinary efforts to get these to grow well in zone 4. Winter protection is a requirement. And none of these plants are particularly free to flower outside of ideal hydrangea zones (7&8). Also, for some undefined reason, variegated hydrangeas always produce lacecap type flowers, even when discovered as sports of mopheads.