The usual questions: what are you looking to do with it, and on what sized tires?
The Currie high pinion 9" is an excellent choice for the rear and can be sent to your door with discs, Detroit, gears, custom width/pinion angle, and alloy shafts for about $3K. Good for up to 36" tires.
If you have more coin, the Tera 60R is a great rear, and of course Dynatrack will take lots of your money for a custom axle. You could also find an XJ D44 for sale and have it regeared.
For the front...why is your D30 not up to the task? It is all the axle you need for 33" tires and can handle 35's in a lot of situations. The usual front mod is a D44. Any number of shops can do it for you, and the best option is starting with a high pinion mid 70's Ford front 44.
Or, if you just don't want both axles to be $5K (it would be hard to get a rear axle this expensive without four-linking the rear suspension), but one axle is fine for $5K, then call Dynatrac or one of the other big names.
I'd go locally if at all possible for the front, though. A rear leaf sprung XJ axle is simple, and low risk for having shipped to you. There are lots of things to mess up with the front. Dynatrac, for all of their top end stuff, could not simply build me a trackbar bracket over the axle to match up with the D44 hi-steer knuckles. Why? I have no clue. They needed to see my XJ.
The shop I used was Foothill Offroad, and they at least understand the trackbar issue, and still f'ed it up and left it too low. The fix was easy at a local shop, but shouldn't have been required. Decide on what front suspension you want before you start - it is expensive to simply replicate the factory design on a 44, and there are better options.
You can search here for a lot of info on this topic (long arms vs. short arms vs. mid-arms...three link vs. four link vs. radius arms...and on and on).
Hope that helps you get started.
Nay
