About the only 1/3 rack width line-level parametric EQ box I know of is the PreSonus EQ3B, but I've never used it, so can't make a recommendation.

I'd reconsider the space constraint. No question that space is an important consideration in a mobile rig, but you may be able to rethink your rig and give yourself a lot more choices in gear.

How about the Baggs Para Acoustic DI? It has four filters, two of which are semi-parametric. The little knobs do tend to be somewhat fragile.

I'm a fan of the Baggs Para, but it didn't sound like what he wanted. He's already using a mic pre (unspecified). A good mic pre might be better than the Baggs - though the Baggs is designed for the very high impedance of piezo pickups. For those who are interested, Baggs also make a unit called the [[url=http://[/URL]="http://www.sweetwat…"]Venue[/]="http://www.sweetwat…"]Venue[/] - basically the Para with a clean boost and a tuner. Very nice.

Well, it's small and it has the eq, and it may well provide a better interface for the piezo than the mic pre he's using. He would probably still want the pre in there after the Para Acoustic.

Yeah, I saw something about the Venue. It looks nice.

I was also going to mention the Symetrix SX201, a 1/2 RU 3-band parametric, but it is probably out of production.

I was also going to mention the Symetrix SX201, a 1/2 RU 3-band parametric, but it is probably out of production.
es it is...and it was a noisey little bastard, too.