If you're not concerned with weight and space, we just carry a $3 thrift store kettle when we take the Coleman stove to boil water for our French press.
Weight / space aren't really an issue in this case. I did a little testing with the kettle that sits on my stove at home and found that especially at higher burner settings I was losing a lot of heat around the sides (it's only 7 inches in diameter and the everest is pretty much a flamethrower when cranked up). I found a cheap kettle that's 10" across to try (should cover more of the heat / flame). If it's still losing a lot around the sides, I'll have to look into finding / making a bigger version of the MSR heat exchanger wrap thing. There's enough straight surface on the sides of the kettle to try it.
I was looking at some of the kettles with the heat exchanger bottoms but it seems like most are either hard to find, $50+ or too small. That concept seems to be more common on pots for whatever reason. I guess a lot of people skip the kettle when camping as it's not as multi-purpose as a pot. But in my case, there's enough room in the Jeep (not taking overly long trips), so I'd rather have the better water pouring ability of the kettle.
I checked out the GSI stuff, but the 1.8 liter version is only about 6.5" across, so it'll have the same issue with heat / flame going around it unless I keep the burner turned down.
