(based on nine-factor analysis, petitioner failed to engage in horse breeding activity with objective of making profit; activity not conducted in business-like manner, petitioner did have requisite expertise in activity and did put sufficient time into the activity, appreciation in value factor neutral, petitioner did not have success in similar activities on previous occasions, petitioner had losses for 17 straight years from activity, petitioner never had any profit from the activity, petitioner had substantial income from his accounting firm and enjoyed the activity; substantial understatement penalty imposed).