Well that made me look like a total douche, now didn't it?
Sorry about that. Well, I'm no Falco Main, and maybe this is just territory that I shouldn't bother to tread on, but I've found that the stun from Falco's Shine is enough to suffice in some situations.
I've gimped a Marth's recovery once by doing this. I jumped off the stage to intercept them and I just used the Shine because I thought it would be funny. And what do you know? The Shine pushed the Marth back significantly enough that no matter what, they had no chance of recovering.
Dunno if I would call it a Shine Spike but it does the job when performed right. And to my knowledge, Falco really doesn't have any other moves that provide good knockback off the stage except for Bair or Dair in contrast to his other moves.
I'm not claiming to discovering anything, but whatever works, works.
[EDIT]
Actually, in a sense I think I would call it a Shine Spike. It's far from as effective as Fox's or maybe even Wolf's, but in Melee, when you shine spiked someone, the hitstun ended quick enough at an attempt for an Up B or whatever recovery. Same holds true in Brawl; in both games you're screwed anyways.
I dunno. Personally I was just talking outloud.