I'm in the planning stages of my wedding and am fast and furiously trying to get info from various restaurants/Casino catering divisions for potential reception options (Caesar's catering, Hard Rock weddings, Maggiano's, Mandarin Oriental-- you name it, I've emailed them), and found a fun place that I can't use for my group, but I thought I'd pass the info along to you all in case anyone is looking for a fun/classy dinner-only reception venue.
I contacted Society Cafe at the Wynn because their food seemed fun and not stuffy, and the decor looks neat. Unfortunately with a group of my size I think it would be at/over their private dining limit (roughly 70 guests), but feel free to contact them if you're interested! They were super nice and got back to me very quickly. It was Jessica Pate and Tania Sanchez who worked with me (jessica.pate@wynnlasvegas.com). I posted one of their sample menus below.
Happy planning!