Apparently this is an unusual item...

I need 4 M6 socket-headed bolts, 70mm long (excluding the heads), and
here's the rub: threaded over the entire length. Everywhere I've tried
only has a thread at the bottom 30mm or so, regardless of overall
length.

Oh, and ideally in s/steel.

I spose I could buy non-fully-threaded ones and tap a thread myself,
but would rather avoid that as I don't have any of the requisite kit,
for a start.

Anyone able to point me at a supplier?

Many thanks
David