I know I'm a bit late to the party here (pun intended), but the Gestalt characters from Unearthed Arcana was pretty much designed for this situation: Essentially you build your character with 2 classes. At each level, you gain the benefits of both classes. You get all the special abilities of each class, the better Fort save, the better Will save, the better Reflex save, the better HD & skill points, and the better BAB.
Thus, a Fighter/Monk Gestalt would have a fighter bonus feat, a +1 BAB, all fighter and monk skills as class skills, monk skill points, monk special abilities, monk weapon proficiencies, simple & martial proficiencies, light, medium, and heavy armor proficiency, shield proficiency, and monk save bonuses at level one.
You still have to keep in mind the limitations of the classes, though - the above fighter/monk would lose their wisdom bonus to AC when wearing armor, and still couldn't flurry of blows with a greatsword.
This tends to create characters which are more survivable in 'stock' D&D situations, and allows parties with smaller numbers to approach the same skillsets as 'classic' parties.
Your group is still limited by the number of actions they can take per round (your fighter/cleric can attack OR heal, not both, and the Ranger/wizard can shoot an arrow OR fire off a magic missle, not both) but you can cover all the 'essential' skills this way.