The short answer is yes and yes :-)

Perhaps the easiest way to create a site programatically is to use the helper classes in EPiServer.UI (that is what is used if you in admin mode creates a new site from "Site Information" under tab Config). The class to use is EPiServer.UI.Admin.SiteMgmt.SiteInformationHandler and method AddSiteSetting. If you do not want to take a dependency to EPiServer.UI you can work against configruation classes also.

To create a folder under global library you can do something like:

var contentFolder = Locate.ContentRepository().GetDefault<ContentFolder>(ContentReference.GlobalBlockFolder);
contentFolder.Name = "MyFolder";
Locate.ContentRepository().Save(contentFolder, SaveAction.Publish);

Thanks for the info - i did find the SiteInformationHandler after reflecting a few dll's, but thank you anyhow!

Cheers for the block info aswell!

One additional question regarding Site creation programmatically/manually:

Is there a way to define the siteDisplayName property programmatically/manuall that resides under episerver.config file? I am using the SiteInformationHandler.AddSiteSetting to create the site and it works perfectly. However i haven't been able to find a way to change the siteDisplayName of any site unless i change it manually from episerver.config. The property seems to be "inherited" based on the site you've logged in. Let's say that i have:

SiteID: "SiteA", siteDisplayName: "Name of site A"

I log on to SiteA and create a new site called "SiteC". The siteDisplayName property will be "Name of site A".

Thanks in advance - I know that there is a way (crossing fingers) ;)

Any possible updates on the latest question?

To do this you need to work with the configuration classes. You can set the value on Settings configuration element and then persist the value with help of EPiServer.Framework.Configuration.GlobalConfigurationManager.

You mean something like this?

// Add host setting 
                List<HostSetting> hostSettings = new List<HostSetting>();
                HostSetting hostSetting = new HostSetting();
                hostSetting.SiteHost = "http://" + siteUrl;
                hostSetting.Language = "fi";

                hostSettings.Add(hostSetting);

                // Create a new multisite to the current instance
                SiteInformationHandler.AddSiteSetting(siteName, "http://" + siteUrl, newSite.ID, hostSettings, false);
                //EPiServer.Configuration.Settings.MapUrlToSettings(new Uri("http://" + siteUrl)).SiteDisplayName = siteName;
                EPiServer.Configuration.Settings confSettings = EPiServer.Configuration.Settings.MapUrlToSettings(new Uri("http://" + siteUrl));
                confSettings.SiteDisplayName = siteName;
                confSettings.EnableSavingOfConfigurationToDatabase = true;

                System.Configuration.Configuration conf = confSettings.CurrentConfiguration;

                GlobalConfigurationManager.Save(conf, RestartMode.None);

Hi Jonathan I tried the code you suggested but I get an error of  "The configuration file has been changed by another program." 

Seems the episerver.config file gets locked by the SiteInformationHandler.  It doesn't implement IDispose either so I haven't been able to get this working.