If it's a question of the application and not the Amiga experience (and I understand if it's the latter), then you might have a look at VistaPro 4.0 for the PC. Higher resolutions, greater color depth, but an identical user interface (plus a smaller chance the OS will fall down go boom because of memory protection issues while rendering a great hunk of landscape).
http://www.vendornation.com/*ws4d-db-query-QuickShow?vp001
