My dream machine :
DPMS LAR upper receiver with left side only charging handle (ambi shown in the pic)
MGI Hydra lower receiver that directly takes AK47 magazines and solves the C Products reliability issue
Rifle length piston kit (will require modifying LAR bolt carrier) or the one above to take the reciprocating charging handle.
no-one seems to be making a match barrel for the 7.62x39, so that is a bit of a tough one. The chamber on my 16" dpms is a bit loose (diameter). I would love a 20" to 24" match barrel and skip the muzzle break.
That leaves the usual choices regarding stock and pistol grip.