Why not start a Knex building request forum or group? Answered
I'm far from knocking you guys because I used to be a LEGO monster. I've also seen some impressive projects and the skills are there in a BIG way.
Why not start a place where people can challenge your skills? Not only will you hone your skills, you will be building stuff you have no clue about and in the process there is no telling what you will learn.
I'm willing to bet there are some cats around here that would be more than willing to keep you in a steady supply of good challenges.