40k conversion?

I've been playing 40k (Rogue Trader) since I got the original hardback
in
'87.  Throughout the years I have kept up with the various revisions of
the
rules, bought minis, sold minis, etc.  Point being -- don't like the
current
set of rules (much less all the drama that *can* exist in the GW world)
but
I do like the minis -- having a special place in my heart for the Space
Marines.

Anyway, has anyone done, or know of, a conversion of 40k to either of
the
ground-pounder rulesets (preferring Stargrunt).