looking for an idea for "fondue alternative" dish, that can be served in a buffet
Any variation of the swiss holy trinity (lardon, cheese and potatoes) is good, but for maximum wow factor, see if you can rent a raclette oven or two and have someone stand by it and slide the molten cheese on people's plates :


Downside is you need a raclette officer on duty (can be done by anyone, its not hard)