Orders for merchandise from 'Celtic Art & Retro-Futuristic Design' are filled by Cafepress. They're billed and shipped separately from merchandise ordered through the other vendors who supply 'Saga Shirts' and 'Ars Celtica'.
There's something I lost when I switched from painting to digital art, and that's the original work. You can't buy the one, single, original piece that I create any more, because there isn't one. So the very first merchandise I wanted to sell online was posters, and archival art prints, made from my high resolution digital works. Everything else - the t-shirts, books, coffee mugs, and so on - has grown from that one desire.