While browsing the Glass Onion archive for Wes/Spike stories last night, I found a few things. One is a story by minim_calibre, Dark They Were, which I hadn't read before and just been recced on a mailing list. It's dark; hence the title--truth in advertising. It's also succinct and searing. Yowch.
Then I stumbled across something I just had to stop and read, because there aren't too many Smallville/Buffy crossovers around, and this was Lex/Spike. There are two stories, original and sequel--I've only read the sequel so far. This morning I went and tracked down the first installment. Haven't read it yet. You'll probably want to read them in order: (1) Change of Pace, (2) Change of Space.
"Change of Space" was interesting as a crossover because it does something I don't normally see; it works within canon timeline--season five BtVS--and adheres tightly to the character arc you'd expect to see for that period, resisting the inclination to diverge. Lex keeps urging Spike to pay attention to him, and as you read, you're torn between echoing him ("Get your groove on, Spike, and for god's sake go with him!") and the growing realization that no, Spike can't and you wouldn't want him to, not really. He's completely focused on the events unfolding in late season five, which he's too caught up in to blow off; he barely even *sees* Lex, who is an unwanted distraction. There's something fascinating about that; it's like a prism of one-sided obsession, an outsider point of view that bends our perception of Spike and makes us realize the depth of his own obsession with Buffy and how the problems at that time are working on him. And again, it was just cool to see how the story played out--both men operating independently on their own terms, terms which couldn't be reconciled.
There were some things here and there in the story that I'd have changed; mostly minor off-key notes. But overall, very neat.