You ask an important question here. Why no public repo? Hopefully my answer here also answers Reuben and Ian's queries on this topic.
Any sustainable FOSS project has a business model. Moodle has the Moodle Partner program and has also benefited (productwise) from 3rd party large grants - e.g. 1) Hewlett Foundation to Open University and 2) NZ Govt. to the NZOSVLE project which I led. The Moodle Partner program is a royalty based scheme for services provided under the Moodle trademark.
There's other business models like dual licensing (which is rather horrible as it's a bait and switch tactic). Or there's open core - which is where you have the core programme open but need to but proprietary plugins to really make it work. These are common models and in my view on the closed source end of the spectrum as the freedom to extend etc. is not there - in either of these models the GPL doesn't extend throughout 100% of the code.
Another common open source model is subscriptions for support. That's what we're doing with Totara. We don't make money from the Partner network - yes there is a fixed annual fee from Totara partners but that's simply to cover the provisioning of services we supply to them. It is a reseller network for the subscriptions for support. So it is very different to the Moodle Partner model and designed to complement.
In contrast to the above models Totara's subscriptions for support come with 100% GPL extensions to a standard Moodle. Compare this to most commercial open source models and you'll soon realise that our model is open.
So why no free download? We have explored various scenarios here and we would not necessarily be averse to a free download. There's implications to consider though and the current position (discussed with Moodle HQ) is that having an open repo would not necessarily be in the interests of Moodle. Why? A free download would need to be supported. In an open community model like Moodle that burden is shared (albeit unevenly) across the community. So if we were to offer a free download, inevitably we'd want to build community around it to help make that sustainable. Btw, we have good experience in doing this with www.mahara.org
So an open download inevitably needs community for sustainability. If we were to build an open community around the Totara distro that would constitute a fork in the community. We don't want that. We're long-standing members of the Moodle community and we are loyal to this community. We'd prefer to contribute our innovations into Moodle directly.
This is why we have concluded that the best option at the moment is to have the subscriptions clearly stated as a value-added service. Totara provides some assurance to corporates that we offer the equivalent of a support and maintenance agreement and many corporates need exactly that or they stay frozen in FUD. If you don't want the service, no problem, Moodle offers an free download supported by the community model. Or if you do want value-added services then there's a lot of very good Moodle Partners and also other service providers around. It's great software!
To Reuben, why is Totara called something different and not 'Moodle for Business'. Moodle for Business would designate that Totara is the official business distro of Moodle. It's not. Remote Learner has ELIS for example. It is the preference of Moodle HQ that we do not use the Moodle trademark in our name or buy-line. We've been discussing the Totara initiative with Moodle HQ from the beginning and there's never been any desire by Moodle or us that these extensions get branded as Moodle.
So why do we have a partner model at all? Because we need to reach and serve the demand in the corporate space. While some Moodle Partners serve the corporate market, many do not. Several Moodle Partners are also Totara partners.