I have been listening to Yasushi Ishii's Hellsing soundtrack for months now and I just can't get enough!
My request is for any knowledge of any other work or albums he has produced outside of Hellsing. I've looked and to me it seems he has only done the Hellsind soundtrack.
I dont know if this will be of much help but a few items popped up when i did a search of the name at http://www.cdjapan.co.jp/
Not sure how much involvement was had in them, hope this site helps.
This explains alot about why I like the Hellsing soundtrack:
"Original soundtrack to 'Hellsing.' The show started airing on October 10, 2001. The driving tension in the sound was created by Yasushi Ishii. Mixed by Masashi Yabuhara who has engineered many of Yoko Kanno's works such as Cowboy Bebop."
Oddly enough though when I do a search for Yasushi the Hellsing album does not pop up. I had to search for Hellsing itself. * ? *