I adore Faith and I love most 'ships so I am trying to find something to fit this. It's really hard because most stories don't have both in them - it's either Faith/Angel or Faith/Spike but not Faith/Angel and Buffy/Spike.
I did find one so far that I noted on my copy was Faith/Angel and Buffy/Spike but I haven't yet read it so I don't know if a) it's any good or b) how well it fits the bill for you. It is:
Can You See by Gillian Silverlighthttp://archive.shriftweb.org/archive/22/canyou.htmlIt is a
sequel of sorts to Avalon's Love is Blind, which is completely spuffy.