Example of a "large" VCL app (120 MB exe, using dll's, DB,...) running on VirtualUI. App is intended for desktop only, but VirtualUI allows to support users on MAC's, Linux... Works just fine, but needs a few more lines of code to handle uploads, downloads, etc. but it's doable. Resource use is heavy, but basically a matter of hardware on the server side.
Go to: http://coolselector.danfoss.com/ and launch "Coolselector Online" a bit down the page.