My wife and I got into blood tracking with a dog several years ago and it has become quite the past-time for us now. We take calls during deer season and track for folks (no charge) both to help them recover deer and to help develop our dog with more tracking experience than I can give him with my own deer.
You want to do a bunch of research into what breed would be right for YOU....not what breed is right for me, the other guys on Tradgang, or for some guy that writes a book. John's book has a decent overview of many of the common breeds used in the US - of course in Europe there are many more breeds used for tracking - and is a good place to start. Keep in mind that you need a combination of prey drive, focus, and intelligence to get the job done - this combination is the key, regardless of the breed. Some breeds just have more potential than others in these respects. Of course hunting bred (European bloodline) Dachshunds (Teckels) are becoming more common for use in the US (due in large part to the exposure from John's book - as well as by some very dedicated breeders that don't advertise as much). Our Oskar is a standard sized smooth haired Teckel from a mixture of northern European and Austrian bloodlines. If you haven't been around one of these European dogs don't judge them by what you might know about pet bred weiner dogs from the US! These weiners can be REAL hunting machines!
We (well actually mostly my wife) trained him with very close input from our breeder - this is IMPERATIVE in my opinion - a breeder that is willing to put in the time to help you - the breeder is (or should be) the expert here, you are learning from them. I would not buy a pup for a blood tracking prospect from a breeder that does not have personal experience tracking. My wife and I probably put over 200 hours working with Oskar specifically on tracking his first 2 years - not so much "training" as "enabling" him to use his innate abilities - and HE trained Katia and myself probably more than we trained him. It is a big commitment to develop a good blood tracking dog. A real tracking dog has no more to do with "running deer" than a pig does with flying. Controlled tracking and "running deer" are mutually exclusive concepts.
We are certainly not experts, but we are learning, maybe slowly! My biggest warning to you is to find a pup you can live with - you will own the dog 365 days a year, and track a few times a year during a 2-3 month period. Also, you won't have a good tracking dog simply by buying a "name" or high dollar dog - the same as you can't become an expert archer just by buying a high priced bow - the innate abilities of the dog (bloodline) and support by your breeder will enable success.
Sorry for the long post...we are really into the tracking thing. It has added a real dimension to our hunting experience, and we've been able to recover quite a few deer that would have otherwise been lost....and that is the REALLY important part!
Best of luck
Ryan