The Black Diamond Alpine Bod is inexpensive, light, no-frills, low-profile, and inexpensive but works well as an alpine harness. It has no padding, on the assumption that your clothes are the padding. One slight downside is that it has no belay loop, which doesn't prevent clipping in a belay device, but does make it slightly more awkward than what you're probably used to.
1. Lightweight...ideally under 300 grams 2. Removable leg loops 3. Gear loops that lie flat and won't interfere with your pack
Something simple and webbing based will do since it's an emergency piece of equipment and you won't need to hang on it unless you fall into a crevasse. I don't understand why people always recommend the BD Alpine Bod since it's relatively heavy (> 400 grams) and doesn't have a belay loop. I own the Mammut Alpine Light although the one that Autoxfil suggested looks sweet and would fulfill all the above criteria pretty well, and even looks like it'll work well for more technical alpine climbing if you end up going into that.
What about the Camp Air CR? 238 grams, padded waist and leg loops, belay loop, gear loops, removeable legs. BD Couloir looks nice too - simple, inexpensive, light (230 grams) and it looks like the position of the gear loops will fit nicely under a pack hip belt. Not sure How you would drop the legs and stay tied in though.
Alpinisto: "Glacier slogging" in itself requires no harness at all, it is only when you or your partner are in a crevasse that a rope and harness become useful. In a rescue situation, the accessibility of the biners to which the rope, anchor, prussiks are attached is vital. In cold weather access is usually complicated by many layers of clothing and cold stiff fingers. In setting up a crevasse rescue haul system you may have a need to attach or un-attach several pieces of vital gear under stressful conditions. A belay loop makes all these operations much less difficult. I have taught crevasse rescue for many years, and this is a major problem. (The Black Diamond Couloir at E-OMC looks fanatastic.)