I own a Fulltone mini deja-vibe. The mini deja-vibe is the same pedal as the deja-vibe 2 but without the wah-like speed control. It has a big speed knob on it though which is easy enough to adjust with your foot.
I've previously owned a sweetsound mo-faux vibe, a simple one-knob pedal which get's into the uni-vibe ballpark but lacks the lush, full organic quality of the more accurate reproductions, such as the deja-vibe or mojo-vibe. It's a cheaper alternative, depending on your budget.
Another one worth checking our is a Red Witch Moon Phaser. It's not actually a uni-vibe clone, just a really great sounding (if expensive) phaser that can do a decent vibe-ish impression. Of the many pedals I've seen come and go, this is the only one I regret selling. Although it does not do a 100% accurate uni-vibe sound, it get's close enough to fool many and is a far more versitile pedal than a straight vibe.