Another possibility would be to go with Dragoons from the War of the Spanish Succession. Several still wore Lobster Pot Helms and Cuirass, and actually did dismount from time to time. At one time, you could get them from Old Glory. The Perrys are also an excellent suggestion. I really like the look of the Warlord Games plastic Pistoleers for their Pike and Shot range, too, but I'm not sure how many of them are dismounted.
Just a suggestion,
Doc