Just had a demo from Richard on this Salamander Moodle and I thought I'll share my info. The demo was closed (I didn't get sent the files), so I haven't had a chance to fully fiddle with it.
SalamanderSoft ltd (http://www.salamandersoft.co.uk) has create a program that will extract data from your SIMS system using Capita's business objects (so it doesn't void your warrenty with Capita) or any other MIS and then import it into Moodle. This will allow you to auto fill your Moodle database with your users and courses.
Salamander Moodle is written in C#, just like SIMS .net, requires SIMS Applications to be installed (as it uses the business objects) and can be installed on a separate server to the SIMS server, (ie your web server). Once it's got the data from SIMS it then inserts it directly into Moodle via SQL. It supports all of Moodle's supported SQL types (Oracle, MySQL, MSSQL). It appears to pull the data into the system memory then pushs it out into SQL so you don't have to worry about temp files holding sensitive data. The application runs as a scheduled task, but can be ran manually.
The extract program appears to offer good onscreen display logging, which it exports to a text log file. They use log4net (Apache log4net - Apache log4net: Home) to make the logs pretty. It uses the admission number or the internal SIMS id as the unique idenifier (key).
The program has an excellent configuration files, XML, that pretty much allows every sort of customization you could ever want. Failing that Richard's only too happy to help.
Now for the bad bits...
Salamander Moodle is a program created by a small company, so it does appear to have a few rough edges, I can't comment any futher then that, I don't know about updates, QA testing etc. It does appear to be quite stable and it does have the excellent support of a small company (ie you speak to a developer).
The program ideally should run as a service. I wouldn't expand on that, it's just a simple fact, I support you could use Firedaemon to run it as a service, or no doube Richard would be happy to make it so (nb. hehe star trek)
Although Moodle can link into Active Directory (AD), which ideally you want to do, SalamanderSoft charge extra for pull data from SIMS into AD as it's a separate program. This basically limits Salamander Moodle to only create classes. This brings me on to my next point.
The price of Salamander Moodle is quite reasonable if you compare it to other VLE, however, Salamander Moodle isn't a VLE, it's just a tool to fully intergrate it into your infrastruture. If you think Salamander Active Directory is double that of Capita's AD Provision, with a qtr of the annual maintainance, having said that, Capita's offering is alot more messy (in my opinion), requiring you to have (ideally) a separate AD, IIS and SIMS server. Still it is alot more safer, basically having a staging server, it's something I would be tempted by. There are "open source" solutions that could also do the job, however I would say Salamander Moodle is alot more cleaner, you can ofcourse create your own. I can't see it being that difficult, however it could get messy.
Windows 2008 supports PHP, so getting Moodle running should be a piece of cake, if you've got Capita's AD Provising just you need to create the groups. Which brings us nicely back to Salamander Moodle.
@Richard: Let me know if i've missed anything or got anything wrong.