There are several tag companies on eBay which allow you to have anything engraved on medical alert tags at a very reasonable cost. Just do a search and you will find them and can order them at your own convenience with delivery right to your home (I've done this myself with a pet tag company that has a medical tag for people, and the engraving is free and it was only about $3 - please email me privately and I'll give you more info if you want it).
Also, here is a link to a site where you can purchase two very nice no-blood logo medical alert items and at a reasonable price:
MJC Products Store
Just look on the left-hand side and you will see at the end of the products list a link that takes you to the No Blood items page.
And it's definitely not overkill to have info in several places related to one's wishes or desires regarding medical treatment, especially for such a serious matter. This is because many times a wallet or purse is not found with an accident victim due to circumstances or the emergency personnel are reluctant to go through personal effects because of possible theft accusations (this is happening in many areas of the country).
So in this day and age, in light of various situations which could arise when one cannot speak for one's self, having identifying information with instructions in several locations or forms regarding any medical treatment preferences or religious beliefs is not only smart but also logical. At least one would know he or she has done everything possible to protect from being given a blood transfusion against one's wishes!