Your only hope for Gorgonia sp. is from Cuba. The Reef Shoppe and Interior Reef have had them. I got mine from Interior Reef. Haha, maybe I should charge $100 per frag and slow down the financial hemorhaging this hobby causes me.
And .. speaking as someone who adores clams .. I don't think you can realistically expect clams to put a huge dent in your nitrate levels, unless you maybe have an otherwise *incredibly* small bioload.. Sorry - but if it were true, I'd have zero nitrates in my 110g right now and I can assure you that I don't - it's low, however, but I also use NO3 Destroyer...