Yes, you can, but it's in a different place, and not as useful. I've hacked my layers to do pretty much as this suggestion says, did it nearly a year ago, and am still hacking it. I also intend to hack some more to give myself more than one custom text module.

For a reason why, look at miss_s_b's sidebar; the custom text is a bit excessive all in one place, we plan to split it up and move it. I have (just) the coding skills to do it, most users don't.

In addition, virtually every other site I compare DW to in terms of rival featuresets allows this, and multiple extra boxes, in some way or other. The current profile setup hasn't really changed since LJ started, so many sites have done better since.