>> Using Multi-Site with Rackspace Virtual Servers:
<< Can you run various domains' webpages
yes.
<< can you host
<<
www.jvz.co.za and ww.acctual.co.za etc in one MultiSite server app.
yes.
<< Can one have more than one Multi-Site server app running at the same time? (using different ports obviously)
yes (although why would you?)
>> And all this for 50/60 USD or whatever per month?
The price depends on the specific server - ie you pay according to RAM and Disk usage.
the bottom end one is with 1 gig of ram and 40 gigs of disk (I think) - and that's about $60 per month plus some bandwidth charges. You also get machines with more ram, and more hard-drive space.
>> When/why would one need more than one Virtual Server?
Partly for Ram - especially if running Sql. But partly for all the other normal reasons - when one machine becomes overloaded then you get more machines. We have 4 machines running at the moment - 1 linux and 3 windows.
Also if you want to do SSL sites then you can't use the multi-host as easily (in that case you're limited to sub-domains).
>> And each one costs you 50/60 USD or whatever per month?
yes. Well no, the linux one is half that.
>> Could one install FireBird/PostgressSQL/MySQL and/or Drupel/Joomla in your Virtual Server
sure, you can do anything you want. You just need to balance Ram and Disk requirements so you get the right server.
Cheers
Bruce