For short boom antennas you might want to consider using a HB9CV design. These are short boom 2 element (both are driven) beam antennas.
Some typical dimensions for a 2m antenna would be a boom length of around 1 foot, Additional elements could be added to increase gain but with the 2 element you should have around 6 to 8 dBi of gain and front to back ration of around 20dB.
I use an HB9CCV design for 6 meters BTW and have had very good results with it.
Scott