150 sqm is small.
Assuming that is for the whole track area (and not to include pitting), and assuming it is a regular shape of 15x10m, you should be able to get a usable micro track in there, but it would be a very tight 10th track.
It wouldn't be up to BRCA national standard for 1/10th, no way near it. I don't know whether the micro section has track size rules. But there are clubs up and down the country that run on tracks that size week-in-week-out.
2m lanes are OK for 10th off-road, 2.4m is better.
Funnily enough someone sent me this link the other day -
http://www.ehow.co.uk/how_8590909_bu...-rc-track.html - it is a guide do building an american-style indoor dirt track. Not sure how accurate it is.
PS Although a lot of people get excited about American style tracks, my gut feeling is that most UK racers actually prefer a good old UK-style multi-surface indoor track without all the big-air features (you couldn't have big air in 150sqm anyway). Its what all our cars and tyres and driving styles are suited to. It's probably cheaper to build and easier to remove as well.