Here's one you can search.... http://www.seedman.com/hp.htm You might also try to find houseplant seeds on ebay.
I used seedman, i orderd about 20 diferent types of palm seeds, and only 3 outtta all of them germinated. I did get a philidendron and a whole bunch of ficus religiosa out of it though. If you want palms rarepalmseeds.com is the best
Any reason why seeds? A lot of the more popular houseplants are cultivars that won't breed true from seed and have to be grown from cuttings or tissue culture. And they are so easy to buy as ready-growing specimens.
I tried seeds jsut to try something new. Its cheaper, and you can get a way better selection, especially with palms.
There's a seller on eBay, Josam5, who is a very reliable seed connection. They've also started including free seeds with my orders, and obviously free = awesome.