hyperion,
Welcome to AT. I don't know of any month spreads that don't involve pulling out a card or two for each week. There is an 8 week spread (do a search in the forum to find it) that's based on a 3x3 grid of cards. In the same vein a 2x2 grid might yield some interesting results:
1...2
......
3...4
12 - First week
34 - Second week
13 - Third week
24 - Fourth week
14 - Fifth week (most months occur over 5 calendar weeks)
23 - Sixth week (some months occur over 6 calendar weeks)
So for 2008 with a Sun - Sat calendar, the breakdown is as follows:
Jan - 5 weeks
Feb - 5 weeks
Mar - 6 weeks
Apr - 5 weeks
May - 5 weeks
Jun - 5 weeks
Jul - 5 weeks
Aug - 6 weeks
Sep - 5 weeks
Oct - 5 weeks
Nov - 5 weeks
Dec - 5 weeks
So for 10 months out of this year, 23 isn't needed. I guess one could either not read 23 or read 23 as additional info for the month. Not a perfect spread, but hopefully it can get you started.
In designing any month spread though, you've got to be careful not to assume a month is only 4 weeks. There are 12 months in a year and 52 weeks in a year. If you assumed 4 weeks per month, then 4x12=48, so you're losing info on four whole weeks.
Rodney