The concept is valid (though I'm not a fan of Pyramining, for other reasons), but I don't think you'll generate much interest or investment.
Two main problems: Firstly, an ROI of 19% for a year, while HYIP-materiel in USD/EUR/GBP investing, is extremely low ATM in the world of Bitcoin. With what I think most consider an extremely stable, constant-rate investment with a publicly identified issuer, BDK.BND, pays 1% a week or 52% a year, and will make 19% in only a few months. Something perhaps considered more risky, BS&T, will generate 19% in a few weeks. 19% in 12 months just doesn't look too appealing.
Secondly: Passthroughs with fees are based on a simple premise: They offer something which the investor couldn't easily invest in otherwise. If Pirate had open accounts and no minimum investment requirements, BS&T passthroughs wouldn't exist; there would be no need for them. (Only possible exception being ones which offered additional "features", such as partial insurance) Pyramining is open and there is no minimum investment.
In short, I just can't see people buying a moderately but not extremely stable passthrough for as much interest in a year as a more stable option offers in a few months using a website with no entry barriers.
Not exactly what you were looking for, but I hope it helps. Good luck.