ARB makes a 35 spline locker for HP44. Not really sure on shafts. I have a Dana 50 and want to use the shafts and inner C's out from with a HP44 center. Just not sure about inner axle seals.
I already have a 44 center with 4.88 gears. I would gain stronger u joints, knuckles, ball joints etc without having to buy aftermarket parts. I don't plan to run anything larger than a 37" tire.