I was asked to make a peanut free cake and was wondering if anyone had any suggestions for me
Unless your kitchen is peanut free I would decline. It's too hard to ensure that every utensil, mixer, oven door handle etc etc are clear of any peanut-containing ingredient. If you're baking from your home kitchen and on the same counters on which you make PBJ sandwiches for your kids, don't even consider it.
(I do offer nut-free products, and no peanut ingredient has ever been into my cake kitchen, I check all labels and my mixer has never had nuts in it. Even then I still say I will do everything in my ability to ensure nut-free but cannot guarantee 100% If the client is ok with that I will proceed.)