Hi Steve;
Thanks for the mail; I’ll keep it short and straight to the point as i've got work coming out of me ears!
Scaling the maf to a larger size is a pointless task and would require tuning to suit, the stock maf housing is perfectly suitable for almost any given application unless you're going for a massive turbo setup (GT35+) and in which case you may as well run without a maf..
Hope this helps guys!