Welcome! I'm fairly new here myself, but have been planning for months. We're having a Hindu ceremony in November 2012 in Tulum (Riviera Maya) (groom-to-be is Indian; I am not). We knew we wanted coastal Mexico, but quickly learned that Cabo was possibly the most expensive place to have a big wedding in Mexico. In addition to loving the idea of a relaxing getaway with our closest family and friends, we also thought we would keep our numbers down by having a destination wedding. Not necessarily true :-). We might have invited 500 in California, but still ended up inviting 300 to Mexico. We're expecting/hoping for about a 50% acceptance rate!
We didn't want to have our wedding at a big hotel or resort, so had the challenge of finding a unique venue that can hold more than a 100 people. My dream venue is a hacienda like those in Merida, but unfortunately those gorgeous relics don't exist along the Mayan Riviera. We did find a replica hacienda in Cancun that can fit 500, but it ended up being too expensive for us. We've landed on a boutique hotel (Las Ranitas) in Tulum. For our 150, venue/food/beverage is going to cost around $15,000. But you're right -- this varies *widely* depending on the venue and how hard your coordinator (if you choose to have one) negotiates for you.
The photographers we just booked (del Sol Photography) were kind enough to send me photos of Hindu weddings they've shot -- I believe these are all in the Mayan Riviera. Check out these links for ideas and possible venues:
Karen + Chuck Hindu Wedding and Reception - Photos by Sol Tamargo
Palka + Joe - Mendhi Party - Photos by Sol Tamargo
Palka + Joe - Grah Shanti + Pithi - Photos by Sol Tamargo
Palka + Joe - Hindu Wedding and Reception - Photos by Sol Tamargo
Raquel + Jay - Photos by Sol Tamargo