Iztaccihuatl would use about the same skills as Aconcagua, but is lower altitude and can be done in a day, rather than the 2 weeks usually required for Aconcagua. I acclimatized by spending several days hiking on La Malinche. If you're interested in Aconcagua and don't have a lot of high-altitude/snow experience, you might want to do Izta as a warmup.
Point Lenana on Mount Kenya is high altitude and a lot of fun. It's not the main summit on Mt Kenya; the two main summits are technical. In general, the area of Mt Kenya is very beautiful and can be explored more casually than Kilimanjaro. Conditions on the summit of Pt Lenana can vary -- sometimes it's quite icy, and then you will want good ice ax and crampon skills. Guides are extremely easy to find and not expensive to hire; you don't need to hire one before you go to Africa. Climbing Pt. Lenana would take about 2-4 days, depending on how much of the mountain you want to see. I did it on the same trip as Kilimanjaro, which was cool but not as fun or beautiful as Mt. Kenya.
Mt. Russell in the California Sierra Nevada is a very cool YDS class 3 traverse at pretty high elevation and with a lot of exposure. It makes a good 3-day backpacking trip.
If you want a big snow climb in California, there's Shasta.