Fat Bikes / Fatbikes

...but will the streets of Chelsea and Wilmslow be awash with them in 3 years' time?

I was wondering what the geo 'rules' are for Fat Bike components - I have an MTB frame with an interesting rear end ('92 Alpinestars Cro Mega LX) and it looks like I could jam a pretty effing large tye back there. Standard canti bosses would likely limit me to standard 26" MTB rims though, and there are no disc tabs.
But... could I put a fat-bike-esque tyre on it, and then run a proper fatbike fork/wheel/tyre up front?

Wasn't there a Surly that a lot of people were running like this? Maybe the disc ready 1x1 with a fat fork/wheel/tyre?

My own 1x1 is a little fat, trials rims and 2.2 Conti RaceKings = that "nothing's stopping me" feeling that must be 10x stronger with a real fat bike.