Custom fields are already in the latest dev. release. They don't look very pretty on joomla 2.5, but they are there.
As far the new release is concerned I would like to have it by the end of february/begining of march.
Don't you mean version 5.0.6? I just checked the JED to make sure this is the latest version.
I'm really happy to hear custom fields is starting to come out. A date field and a checkbox is a must have for me! I would be so excited to have this. The date field is for signing when a user climbed so and so peak. Here's a visual example:
Also note that a checkbox could be handy for some sites that say "agree to terms before commenting". There are other uses too, but you get the idea.
I promise I will give you a big break after this! Custom fields would be like Christmas to me. If it makes you feel better I stayed up late last night dealing with a totally hacked website that created a lot of mayhem.