In Pocket Informant's Monthly view, if you tap on a date, it splits the screen to show you that day's appointments in a scrolling list in the bottom third of the screen. It's an excellent choice for GTD on the PPC platform.
PocketInformant 5 will allow you to do this - setup the Month view to allow Inline detail. You get all 30/31 days and when you click on a day, a pop-up box details the appointments (+ any tasks due if you have that option selected)
If I am understanding you, you want to read your appointments on a PocketPC while in a monthly view?
I don't know about your eyes, but with my Toshiba e740, I would have a box about .4 inches wide and .5 inches high per day, if I went with a 5 day view instead of a seven day. I think that with a font of 4pt. I might get all of 12 letters inside it. But I can't read that at all. I had to go up to 8pt. before I could make out words, which left me with five letters across.
There are ways you can put icons in those boxes to give you a better idea of what's on your plate "at a glance" but I don't think I have ever seen any software that tries to do what you want. Good luck, and of course many would be interested in what you do find to work.
Poket Informant is what you want, I believe. The thirty days are there and you can tap on the screen and find the entire day in view through the open window or you can set it up in other helpful ways.. Great program for GTD and one you really should trial download!
This is a handy tool for both Outlook and Pocket PC. http://www.windsorinterfaces.com/
Pretty amazing appliacation. It is easy to use and gives you a large view to single day view in a smooth transition.