Both Toyota and Nissan have "full-sized" pickups (Tundra and Titan, respectively) that approximate the Silverado, with V8 engines in the 5.4 to 5.6 liter size range. I think a redesigned Titan is due out from Nissan, along with the diesel power option. Don't know about the Toyota, but neither company makes drastic or frequent changes to either pickup.
All I can tell you is to go test drive them and do your homework on Edmunds and similar websites. As for lease deals, I really don't know what is available on pickups.
Thank you.