First sale doctrine says you should be okay,
however trademark law has come into play and has caused problems for people. As has pr.
If you google
urban outfitters crownfarmer you'll see UO ran into problems constructing one garment by cutting up another.
I would suggest that what you're proposing is legal, but could involve you in legal trouble anyway. I would further suggest that you contact a lawyer for better advice than we can offer, and that way you know how you'll act if you get accused of anything (i.e. you can have a letter drafted to fire back).