I don't think playing fair and doing it on your own necessarily means you rule out your family. After all, you've helped them pay for the house, and you've helped them develop good credit. If you approach them for help with your credit, it certainly seems fair to me. There's no shame in doing business with your family, especially if their family corporation owns your house!
What would happen if the family member whose name is on all the paperwork added you to their credit card(s)? You might get the same boost described in the "shady" deal above, but with a family member who you trust and who knows you are responsible with money.
I really don't know if it would work, though. I'm not a pro at this. Maybe a credit counselor would be a good investment for you. Good luck!