Hi Steve,
I too have a medic-alert dog tag, plus they supply a wallet card stuffed full of your medical information, its an annual subscription service, as a medic can call the medic-alert number, quote your unique number and get the full medical details, sometimes some of your medical conditions you don't want accessible to everyone.
As for the medical ID cards, I'd suggest printing your own and laminating it, if you're using an A4 sheet print a number of them, but remember to make them smaller than a credit card.
When they've been laminated cut to size, you then have your medical record as you want it and a few copies of it as well. Often worth leaving one in your car, laptop bag and wallet(s)/purse(s).
As previously discussed though, its still down to a medic taking the time to locate the information about you.