What's wrong with Megaman 9 and 10? They are great games, true to the original NES series in most every detail. I'd even argue that 9 and 10 lead directly into the X series, as 9 has the first mass Maverick uprising (Protoman is technically the first Maverick, but this was the first after him) and 10 show Wily experimenting with computer viruses (something Zero spread prior to X-1, which caused ALL the problems in the X Series).
I'm pretty sure it's even possible to get 9 and 10 on reproduction carts if you really want a physical copy.