In case anyone seriously considers doing something like this, you should know that vandalizing or removing political yardsigns is a misdemeanor in every state and can carry fines of $1000 and up to 90 days in jail per sign.
Wouldn't it only count to political signs placed by the party in question? I don't think making your own sign would count. That would just be normal vandalism wouldn't it?
If it's your sign you may do as you please with the sign. Displaying it in your yard may be less straightforward, as it may no longer count as a political sign and fall under a local sign or art ordinance. Probably.