Sure! No changes to BlogEngine.Core were necessary and the the diff for the BlogEngine web application is below. Note that those changes aren't as much Mono specific but rather platform specific. They deal with Windows vs Linux differences:

diff --git a/site/blog/App_Code/ExtensionManager/Manager.cs b/site/blog/App_Code/ExtensionManager/Manager.cs
index 8807d99..1bf9d9c 100644
--- a/site/blog/App_Code/ExtensionManager/Manager.cs
+++ b/site/blog/App_Code/ExtensionManager/Manager.cs
@@ -101,7 +101,7 @@ public class ExtensionManager
         xs.SaveSettings(x);
         SaveToCache();

-        string ConfigPath = HttpContext.Current.Request.PhysicalApplicationPath + "web.config";
+        string ConfigPath = HttpContext.Current.Request.PhysicalApplicationPath + "Web.Config";
         File.SetLastWriteTimeUtc(ConfigPath, DateTime.UtcNow);
         break;
       }
diff --git a/site/blog/Web.Config b/site/blog/Web.Config
index 564c954..73449ca 100644
--- a/site/blog/Web.Config
+++ b/site/blog/Web.Config
@@ -20,13 +20,13 @@
     <clear/>
     <add name="LocalSqlServer" connectionString="dummy"/>
     <!-- Mono complains if LocalSqlServer isn't specified -->
-    <add name="BlogEngine" connectionString="Data Source=|DataDirectory|\BlogEngine.s3db;Version=3;BinaryGUID=False;" providerName="System.Data.SQLite"/>
+    <add name="BlogEngine" connectionString="Data Source=|DataDirectory|/BlogEngine.s3db;Version=3;BinaryGUID=False;" providerName="System.Data.SQLite"/>
   </connectionStrings>

   <appSettings>
     <add key="BlogEngine.FileExtension" value=".aspx"/>
     <!-- You can e.g. use "~/blog/" if BlogEngine.NET is not located in the root of the application -->
-    <add key="BlogEngine.VirtualPath" value="~/blog/"/>
+    <add key="BlogEngine.VirtualPath" value="~/"/>
     <!-- The regex used to identify mobile devices so a different theme can be shown -->
     <add key="BlogEngine.MobileDevices" value="(nokia|sonyericsson|blackberry|samsung|sec\-|windows ce|motorola|mot\-|up.b|midp\-)"/>
     <!-- The name of the role with administrator permissions -->
diff --git a/site/blog/admin/Extension Manager/Editor.ascx.cs b/site/blog/admin/Extension Manager/Editor.ascx.cs
index 6256f64..f11e3a0 100644
--- a/site/blog/admin/Extension Manager/Editor.ascx.cs  
+++ b/site/blog/admin/Extension Manager/Editor.ascx.cs  
@@ -66,10 +66,11 @@ public partial class User_controls_xmanager_SourceEditor : System.Web.UI.UserCon
         {
           if (type.Name == _extensionName)
           {
+      char dirSeparator = Path.DirectorySeparatorChar;
             string assemblyName = type.Assembly.FullName.Split(".".ToCharArray())[0];
-            assemblyName = assemblyName.Replace("App_SubCode_", "App_Code\\");
+            assemblyName = assemblyName.Replace("App_SubCode_", "App_Code" + dirSeparator);
             string fileExt = assemblyName.Contains("VB_Code") ? ".vb" : ".cs";
-            fileName += assemblyName + "\\Extensions\\" + _extensionName + fileExt;
+            fileName += assemblyName + dirSeparator + "Extensions" + dirSeparator + _extensionName + fileExt;
           }
         }
       }

Given that I'm not much of a blogger, don't take my opinion for granted. Having said that, I like what BlogEngine.NET offers in terms of both functionality and the backend. I previously used blogger.com and I must say I like BE much better. What is definitely nice is its data storage backend configurability. So far, I haven't found anything which I would count as an argument for not using BlogEngine.NET.

Yep, on my own Debian/lenny server. There are no problems with stability, it's been up for 7 or 8 weeks now without any issues.