I am just a novice at the game, only had it a few months, but it occurs to me that even making a race like this for homebreds only would be very easy to breed a poor horse.
I have been looking for a 100% extra speed horse (no luck yet) but have re-started a new game about 40 times to look for one. The poor quality of some of the horses at game start up would make it easy to breed a rubbish colt with a rubbish filly and produce a rubbish homebred.
This idea has some appeal as a bit of fun, but would be very easy to be abused by anyone and very hard to implement a set of rules. Every horses lineage would have to be checked after upload to Tom.
What about an age limit? 3yo only?
I have been trying to achieve one of the game objectives and win a race with a 15yo. My 100% potential 3yo horse has only about 15% potential as a 15yo. I saw a post where someone had a horse that was a 100yo
http://www.startersorders.com/phpBB2/viewtopic.php?f=19&t=16090&hilit=oldest+horse