Have you read any of J.S.(Joseph Sheridan) LeFanu's work? His work is quite similar to Blackwood's. A website called The Literary Gothic has a brief bio of LeFanu, and it also has links to other websites where you can read more info about LeFanu: http://www.litgothic.com/Authors/lefanu.html
I've bought several books by LeFanu at Dover Publications. I like Dover because they provide unabridged reprints of lots of previously out-of-print books: http://search.store.yahoo.net/cgi-bin/nsearch?catalog=doverpublications&query=j.s.%20lefanu
If you go to the Dover Publications site to see what they have on LeFanu you'll also find other similar authors like Willkie Collins and M.R. James as well.