Poser-ready houses seem to be doing well, but there aren't enough cars. There are more than enough vehicles over on Turbo Squid, but most are for MAX. If you could model some good MAX-like sports cars to be poser-ready props, I think they could do well. Hankster made a few good cars and they were quite likeable. I don't know how well 'bots and tanks will sell with the 'rosity ladies. Some guys might go for it. I suggest common and classic cars to start with, because you can find resource blueprints, images, and textures for those. With fantasy vehicles and 'bots you'll have to wing it more. The only thing you'll have to rig is the doors and wheels, the trunk and hood if you're brave. People seem to like it when you make a good car interior too.