I just started a level 5 game last night with this conundrum, actually, with only 3 players (myself being one of them). The DM is cool with revising characters after the first session to fit players' playstyle, and the kender rogue (eek, run!) and elf warlock are most likely going to turn into a kender swordsage and elf duskblade. I ran a druid, and am switching to my original GOD wizard, due to inability to rein in the awesome, and since I have access to a domain that's swappable, can double as the healer/trapfinder depending upon which domain I'm using. And if nothing else, there's always Summon Dead Celestial Monkey for that
The kender - Uses a gnomish quickrazor to awesome effect, and effective trapfinder. Skills through the roof. Might not even need the swordsage makeover, due to CC/flanking/quickrazor being badass setting up SA
The elf - My wife's character...if I'd known she wanted mainly to melee, I'd have given her glaive
Duskblade feels more fitting though, since she melees more than blasts, and makes her a mini-buffbot.
My Wizzy - Going into War Weaver, nuff said. Probably going to cap out with Incantatrix for nifty Tapestry tricks, and definitely snagging a ToAL.
Once we get a little higher level I'll be packing a summon/bind for extra tanking, and most likely will be able to ensure the two ladies are never without enough buffs to make their lives easier. We started without any magical items (2nd Ed style DM), but with enough buffs even that shouldn't be an issue. And afterall, a prone, entangled, exhausted melee opponent is pretty well just dead meat anyhow