I think this would probably involve quite a bit of customization, because the blog control is populated from the blogs provider. Although you might be able to change the provider in the Data field of the control, the control is hard coded to use the "Publication_Date" meta field (not the Event_Start which you will likely be using!)
it shouldn't be all that difficult to develop something like this. I did this for our city calendar (www.mcallen.net/calendar
) using the standard asp.net calendar control. granted it's a little more elaborate than your needs but the concept is still the same:
1) grab all the dates for the given month using the events api
2) handle the dayrender event for the calendar control. if the event date is present from step 1, chnage the content of the control by changing the background color, adding a link, etc..
here's an example article with a basic simple example: http://odetocode.com/Articles/223.aspx
i hope this points you in the right direction for getting started, let me know if you make any progress and I'll do what I can to help!