The experimental children's records mentioned in the article are absolutely worth your time, as well as the aforementioned Lucifer, but anyone interested should also hear "Party Machine"[2] (co-produced by Russell Simmons) and the 32 minute epic "Icarus"—both bonus tracks on Haackula[3], a 2008 collection of previously unreleased material. There's also some really good stuff on Bruce Haack Remixes[4] which came out on Stones Throw in 2012.
One of my favorite rap songs in recent memory is Micah James' "Blow Job (Give Up)"[5] which samples and builds on a Haack song by the same name.
[1] http://www.discogs.com/Bruce-Haack-The-Electric-Lucifer/mast...
[2] https://www.youtube.com/watch?v=Cox-6Lwx0Nw
[3] http://www.discogs.com/Bruce-Haack-Haackula/release/1377215
[4] http://www.stonesthrow.com/store/album/various/bruce-haack-r...