m16 studding work instead of ballscrews ?

[irving2008]

but have just bought some M10 A2 Stainless (which works out at about £3.87 a metre)....which looks like it'll be much better. I intend turning the ends down to 8mm to fit the skate bearings I have supporting the rod (which in turn are held by SK16 mounts).

M10 A2 is good; the main issue with the smaller threads is the pitch, M10 is 1.5mm, which makes for slow traverses unless you gear up but then that adds cost/complexity. TR12x3 is £11.40/m (at Marchant Dice) and arguably the best mid-range compromise IMHO between cost and performance