I found this timely as I am in the same situation, although I did do a brief stint of setting up the x86 option he also mentions. In the end I decided it just wasn't worth the hassle. I'm happy to see this article because I had been wondering what commercial router to get to run dd-wrt. I got burned on this once before when I bought a Netgear on sale at best buy a few years ago: it looked like the same as a model that ran dd-wrt and I even got an assurance from the sales person that it would run it, but when I got it home discovered that Netgear had replaced the inwards with a cheaper, incompatible version of the CPU and half the RAM, without updating the model number. Grrrr. I felt like they were taking advantage of the popularity of the open source mod to pull a bait and switch. I'm happy to see that routers now actually print the open source compatibility on the box. It feels like a rare victory.
You've had to be careful about this for years. There has been 10 revisions of the WRT54G and something like half of them don't work with DD-WRT/OpenWRT.