2.05 Glide slope
I know of several ILS approaches with glide slopes other than the standard 3 degrees. The lowest of which I am aware is the ILS to runway 25 in Kodiak, Alaska (ADQ or PADQ) with a gs of 2.05 degrees. This is due to terrain, and the approach/missed approach criteria (TERPS). In addition, due to prevailing winds and often low ceilings, the advantage of a lower than standard GS is that it allows you to get to a lower altitude (below prevailing ceilings) before the missed approach point. Because of the terrain in Kodiak, the MAP is farther out.
In Ketchikan Alaska (KTN or PAKT) the glide slope for the ILS runway 11 is 3.61 degrees, although I believe both Kodiak and Ketchikan are tailored approaches sepcific to Alaska Airlines.