klc,
The many reason most are buying Grafted forms of Adeniums is because they do not come true to seed and they want a particular bloom that is available to purchase.
The good hybridizers of these plants grow hundreds, thousands or more seed to produce a small number of special blooms.
You can buy seed grown Adeniums with very beautiful blooms. A lot is an individual preference as to what they like, i.e. plant (caudex) shape, bloom, leaves.
Many on this site have found some very nice plants at Lowes, HD, Walmart.
Best to buy a plant in bloom or a grafted plant if you desire a bloom of choice.
The seeds are not difficult to grow, but depending on what conditions and growing season. They can bloom as early as 6-7 months to a couple years.
On ebay. Try adenium_Ko or Orient Adeniums.
Hope this helps,
Rick