Your not going to find resorts comparable to Couples in any other destination than Mexico and the DR. Mexico actually has the better, more lux AI resorts than Jamaica. The Couples resorts are really sub-par compared to some of the high end AI resorts in Mexico (IMHO). Excluding the one destination that offers everything you are looking for will make this a huge challenge for you.

You might look at Sandals in their various locations. However, my experience with them is that they are overpriced for what they offer. We found the food at the Sandals Grande in St. Lucia to be terrible.

Here's a list of AI resorts in the Caribbean. It might help you narrow done your search:

http://www.caribbeanallinclusive.com/caribbean_all_inclusive_resorts.cfm

Thanks KVR! Do you have specific resort recommendations that meet those criteria in either Mexico or the DR if we do expand our search?

With that budget you could do a luxury all inclusive in Barbados for a week since it is off season.

I would look at:

Turtle Beach
http://www.tripadvisor.com/Hotel_Review-g1183186-d147780-Reviews-Turtle_Beach_by_Elegant_Hotels-Dover_Christ_Church_Parish_Barbados.html

Crystal Cove
http://www.tripadvisor.com/Hotel_Review-g147265-d147778-Reviews-Crystal_Cove-Saint_James_Parish_Barbados.html

In Mexico look at the Secrets Resorts, The Iberostar Grand Parasio, the Royal Playa del Carmen, The El Dorado Maroma Beach, Valentin Imperial Maya, and the Zoetry.

In the DR look at The Majestic, the adult only Iberostars, the Excellance and the Secrets resorts.

Antigua has some great all-inclusives. I stayed at Sandals -There is also Galley Bay, St. James Club, The Verandah..... And if you really want to splurge...check out Palm Island..since it's low season, that might work with your budget.

It is a pity to be restricted to certain destinations because of the perception that AIs on other islands are in some way inferior to those in Mexico, DR and Jamaica. There won't be montrous sized hotels on the smaller islands.

As others have mentioned, there are several choices in Antigua, Grenada, Barbados and even Tobago which is a gorgeous little island.

I would add Royal Hideaway to the list for Mexico. It is a top notch luxury adults only AI on a very nice beach.
It has everything you are looking for all included!

When the OP stated they wanted something even better than Couples in Jamaica, unfortunately it's a true statement. Though there are AI resorts in other parts of the Caribbean, the places currently mentioned will probably not meet the OP's expectations of "We would like to find something similar with just a little bit of increased luxury (particularly regarding the room)."

Having been to over 15 AI resorts throughout Mexico and the Caribbean, I still haven't found any better lux AI resorts than Mexico.

Odin, I'm sorry that I hurt your feelings regarding my comments on AI's in Barbados, which I throughly stand behind, but, I don't appreciate you contridicting or mocking every comment I on make on these forums. I have been posting since 2003 and my comments have been well received an respected by many especially when it comes to AI resorts, which I obviously have way more experience with than you do.

The Iberostar chain is very nice. We've stayed at the Grand (adults only) in both Mexico and Jamaica. The rooms and restaurants were virtually the same at both locations. The rooms are very nice and the food across the board was very good at the four restaurants. I wouldn't hesitate to go to an Iberostar Grand anywhere.

If you want off-the-beaten-path you might want to look into Grenada. We just returned from our first trip there and loved it. As Odin says there are some all-inclusives.

We also stayed at the above-mentioned Galley Bay in Antigua a couple of years ago. That's one of those "all-inclusives" where you have to pay for a lot of things. One of their restaurants wasn't just an added surcharge. It was full-price! And if you took a bottle of house wine away from the bar area they charged you for it. We found the whole experience rather unpleasant and would not return, especially since the food was mediocre (despite glowing reviews on Trip Advisor).

Barbados is a beautiful island with a lot to offer so you might want to look into the all-inclusives there. Dontcallmecass gave you some suggestions above but there are others I believe. See KVR's list and in addition I think Bougainvillea Beach Resort offers an AI package.