Good advice cammer.
Here is my experience from rockcrawling and UROC racing. Even with a mild setup, we have never been able to make a 44 live. Even with Moser stuff and then with Warn chrome moly axles and the one piece joints like CTMS and Longfields. I have spent enough money on D44 stuff to build a custom 60!
If you could make them live in a racing environment, you would see a lot of them because they are cheaper!
We did a 609 for our comp buggy. Front and rear steer. Follow the link in my Sig line.
Deddenbear inner and outer knuckles, and Sunray Engineering 9 inch center and tubes.
We run a Strange 35 spline aluminum center in the front and Nodular iron Strange in the rear.
The aluminum centers do not live long in the rear when you are launching on rock with the whole weight of the rig on the rear and super low gears . I believe the aluminum housing "flex's" enough to let the gears eat each other. We ran Superior custom alloy shafts and chrome moly joints.
You can do this set up your self. Use a late model 9 housing, retube it and use the D60 knuckles etc. The Deddenbear knuckles can be ordered in different tube sizes, but they are heavier tha a stock 60 knuckle.
If you use a detroit in the 9 center section, USE A 35 SPLINE setup!
If you use smaller shafts and smaller joints, when you break the shaft or joint under power, the resulting shock load WILL KILL your Detroit! Expensive lesson. I have saw 4 killed this way. A 35 Spline Detroit is not neccesarily stronger ,but their will be LESS chance of a major shock load from breakage if you use the heavier shafts and joints.
The 9 can be modified to oil upside down! Our buggy has had no problems. Have not had to use a HIGH 9 yet.
OR you could just do a good old D60. Hard to beat! Just use some good shafts and joints and be done with it.
You can get used axles, New shafts, and great service from Doug (High honda) at Extreme Axle sales. http://www.extremeaxlesales.com/index.asp
He is a great guy to get parts from and has the BEST prices on shafts, joints, and D60 Hardware.
If you spent the money to get the horsepower, you HAVE to spend a little on the front axle!
I agree with Cammer on the Kingpin setup. I like them awful well.