Here is a blog I found just now. It's a rather ironic name but amoungst some of the metal albums there are a couple of (what I presume to be) rare/obsucre punk/hardcore albums.
http://punk-sucks.blogspot.com/
Also, this blog has a few punk/hardcore, so heres some more listening.
http://skafunkrastapunk.com/
Click on the title of the file you want and it should take you to it's specific page where theres a icon of a floppy disc, this is the download button.
Some of this sounds really cool. "5 Knuckle Chuckle", Combining the best of ‘80s hardcore with tight rhythms and catchy melodies, the Five Knuckle Chuckle debut Charliee Horse is fueled by a common anger and hatred; charged with youthful passion, and purposely delivered with renowned intensity by producer Simon Head (Red Fisher, Random Killing).