I just bought a Vita recently. I bought SH1 on PSN a couple years ago to play on my PSP. I am in the US. When I look at my PSN purchases, this is what I get:
For comparison, other PS1 games I bought on PSN can be downloaded just fine on my Vita:
But i talked to someone recently who claimed he downloaded SH1 for his Vita from the EU PSN store. So I dunno, it seems to be available somewhere, but I can only play on PS3 and Vita.
Though the idea of making another account is interesting, I might try that.