I've seen some collages made with pictures of celebrities in or on places you normally wouldn't see them. 
example:  picture of keith richards pasted on a "Just say No" ad

Flip through some magazines....think irony, think humor.

You could always get a frame from the thrift store, paint it and frame it.  You could decorate the frame with a sea theme.

I think you would probably be okay using the house paint.  For extra permanency you could turn your clothes inside out and heat-set them with an iron.

We also have a large dog, a 75lb greyhound.  I found an inexpensive big pillow type bed, but the stuffing gets clumpy. I've been looking for an alternative and the crib mattress is it!  Thanks!