RFID reader for a keyless residential entry system?
Sparkfun has some RFID devices that are fairly DIY ready. Here is a link to one:
http://www.sparkfun.com/commerce/product_info.php?products_id=8419

This is if you are wanting to actually build your own device to do keyless entry. If you are wanting a pre-built key-less entry you might need to look else where.

EDIT:
After answering I did realize you mentioned that you wanted reliability and ease of integration. My solution probably isn't the best for this requirement.
Look at this site: http://www.househacker.com/permanent/DIY-RFID-Access-to-your-Front-Door