Regarding hosting the dotLRN stuff under openacs.org, we've played around with setting up subsites for various subprojects (OpenACS, AOLserver for our custom changes to that). There's a dotLRN link there but ignore it, it's just there as an example. And currently they're not subsites because something seems broken when subsites and etp try to play together, or subsite itself is broken in the install (works at home for me, though).
The idea here isn't to try to twist arms to get project like dotLRN to host under openacs.org, it is very important for such projects to have every opportunity to establish their brand in their target market.
The direction is to be able to offer hosting later for those projects that don't want to be bothered with hosting their own site. Using ACS subsite means projects that host at openacs.org can have their own look and feel - they can have banners that are entirely yellow and maroon if they want - and can control membership if they want.
And the host node map allows for mapping an arbitrary domain name to an arbitrary subsite. That's what we do with greenpeace.org and greenpeace.nl, for instance.
But offering hosting as a service to an interesting project is much different that suggesting such projects should host here. I personally think it's fine that dotLRN is hosted elsewhere.