14" rims do clear stock sierra front disks.
I have an ancient LJ50 "wide wheel pack" wheel and tyre - it's a 14" Gates Commando, which despite no looking anything like a Baja Claw, would do excellently in sand - that's what they were designed for.
The photo is of a Jeep rim - not what I have at home. It was blogged form JP magazine. Tyres are the same though.
Steve.