I’m currently working on magento shop and decided to publish some my simple extension in http://www.magentocommerce.com/magento-connect/ store.
I did simple extension that show login popup dialog when user trying to add item to cart. In fact you have a handler that can show login popup when you need that. So you can use for any html element.
What benefit do we get. We make user to login faster and therefore we get user info one step faster. Then we can show special prices, promotional offers and others.
So how are interested are welcome to Magento Login Speed Up Extension