Dave.. Wrong question... do not ask "Hey honey! What if I put a Santa Maria pit in the backyard."
Everyone knows that a bloke does his best thinking whilst sitting on the can, so next time you are in there just refine the idea and then have a eurika moment and ask is she has any objections (but not too loudly). We all have noticed that the missus never listens to us when we are sitting and schitting so talking to her thru the shut door, you do shut the door dont you?, she will not be able to decypher the words from the usual grunts n groans... therefore no objections!
Make sure you plan ther job thoroughly so that there is a minimum of time between bills so that they wont show up on the statements untill its well under way. Dont try to be sneaky on do it in bits and pieces coz they always notice, just order up large then rip all the packaging so that the store wont take it as a refund.