I'm looking for bands similar to the kind of music Earthless (who aren't on the site, despite being metal enough I think, maybe they haven't been submitted) and Zebulon Pike play.

You know those crazy sections of prog rock songs where they go off on instrumental tangents and play around with certain musical themes and whatnot? It's basically that, but all the time, and heavier. I'm not sure how else to describe it, so hopefully some of you have heard these bands or can spare the time to give Zebulon Pike a listen on myspace.

I'm not looking for Blotted Science/Behold...the Arctopus/etc-esque bands or progressive metal in the Spastic Ink vein, not laid back enough. I guess a doom and/or stoner vibe is something both of these bands share (and possibly psychedelic touches). Any ideas?

Afraid I don't know the bands you mentioned, but a band that springs immediately to my mind is 5ive, or 5ive's Continuum Research Project as they became (to avoid confusion with the boyband!). A guitarist/drummer duo, they create incredibly heavy spaced out psych/sludge jams, kind of Hawkwind meets Neurosis maybe? The first album ('5ive') is my personal favourite.

Also, I know they're not Metal, but I presume you're aware of Ozric Tentacles? No band can touch them for sheer instrumental prog/psych/fusion noodling.


Edit: Just listened to Zebulon Pike, that's awesome. You'll definitely like 5ive, though they're not as structured as ZP.

Mammatus.

They aren't really jam, but Blotted Science is a really great instrumental band.

The OP did state he's not looking for bands like Blotted Science...

Windmills by the Ocean may be something close to what you're looking for. They're not particularly prog oriented by any means, but they definitely have that laid back, spaced out vibe about them.

Well older Pelican or Tides might fit what you're looking for if you don't know them already. Either way, thanks for introducing me to a really cool band in Zebulon Pike.

I would check out Pelican, for sure.

Would Dimaension X count? Download links are in my signature. Instrumental jamming type project.

Capricorns are definitely worth checking out as they are an awesome and very laid-back instrumental metal band.

Umphrey's McGee is a total jam band, but the occasionally they actually have legitimately "metal" parts- thrash-style riffs, double bass, blastbeats, metallica-style melodies with dual guitar harmonies, etc.
I thought it was pretty bizarre when I first heard it, but I'm pretty sure the dudes in the band dig metal a lot, so those parts aren't simply put in as a joke or to be ironic. Can't recommend 'em if you don't like jam band shit (me included), but of all the shit I've heard these guys are one of the best.