Well, there's the Sims wiki here: http://simswiki.info and another one here: http://sims.wikia.com/wiki/The_Sims_Wiki but I've never heard of either one being a source of builds. Once the Gallery's back up and running after the major maintenance (might take a couple of day) you should be able to find plenty. If you're going for putting them in Newcrest, the largest lot is a 50x40 and only one of those, so stick with that size and maybe 40x30 and see what you can find in the §150K+ range. If you want to go up to a 50x50, there are two in both Oasis Springs and Willow Creek if you want to demolish the two large parks, otherwise just one. For 64x64 lots there are two in Windenburg (Get Together) and I think one in Brindleton Bay (Cats & Dogs). (There's also one in San Myshuno, the City Living world, but it's a locked lot type so can't be changed to residential).