I'm having my wedding at Now Amber/Secrets in Puerto Vallarta this November. Their wedding packages include 25 guests (including bride & groom) and then of course you can add more guests for an extra cost per person. The resort is new (opened in 2012 I think) and from what I remember is very wheel chair accessible (elevators to every room, restaurant, and to the pool).
They have different options for where you want to have your ceremony (beach, poolside, gazebo, lobby) as well as you are able to choose different locations for your cocktail hour and reception. They have indoor and outdoor options (some outdoor options better for smaller groups). I am having only about 20 people at my wedding and we are having the ceremony on the beach and the cocktail hour and reception on a private outdoor terrace on the resort. There are options for renting a mariachi band, DJ, or just microphone and speakers for dancing, and they also have a club on the resort which opens at 10pm which is really fun! We are planning on having our after party and the majority of our dancing at the club after our reception. That way we can avoid the expensive cost of the DJ.
Now Amber/Secrets is a 5 start resort and is more on the expensive side, but totally worth it! We did our group booking in Jan/Feb of this year and were able to get a really good deal (about $1550-$1650 for double occupancy room for seven nights with direct flights). The prices increased almost $1000 throughout the year and are now actually sold out! So the group booking early really worked out for us (this was through Westjet and departing from BC Canada). We had visited this resort previously to being engaged, and once we got engaged, I knew that is where we had to have our wedding! The resort is amazing! Anyways, I hope that gives you an idea about the resort, but like Perianjay said, its always helpful to talk to a travel agent as well because they know other options in the area and can maybe compare different resorts for you.