UPDATE: Got it done this weekend. Pressing the bearing onto the hub was a challenge, but I managed to get that part done with some patience and a really big vise. If you are going to do this yourself, you need to plan on taking the hub and bearing to a machine shop or someplace where they can press it in for you. The part that had me the most worried, reassembly with the axle shaft in place crowding out the bearing hub bolts was not a problem. After I had pressed the hub into the bearings, I was easily able to bolt the four bolts onto the axle carrier since the axle shaft was pushed in so much. I had plenty of room to put a socket on the bolts, although I had to use a swivel adapter like Infinitifan25 mentioned for one of them. The others were fine with a 5 inch extension that was slim enough to avoid the outer CV joint bulge. I would just put the socket on, hook up the ratchet with the extension (or swivel adapter) and crank them down tight. It was so easy I kicked myself for taking so long to address it. Then I put the large axle nut on and tightening it down pulled the axle shaft up tight into the hub. One new cotter pin, remounting the rotor and caliper and wheel, and the job was done in less than 1/2 an hour.
So, being an average mechanic would I do it again? Absolutely. I think this is in the realm of the average shade tree mechanic IF you have these tools that I found essential: 32mm socket to remove the axle nut ($14 at O'Reillys), 1/2 inch driver for the 32 mm socket, 3/8 inch driver with 4-6" extensions and a swivel adapter, a gear puller that I needed to get the hub started off (I find this tool useful for lots of stuff - mine is only an inexpensive two arm; a three arm would be better), a 3/8 breaker bar so you don't ruin your 3/8 driver, and some pipe to give you leverage to break bolts loose, jack stands, PB Blaster (the ultimate penetrating lubricant) and a shop that will press the bearings for you.
If I had to do it again, I think this would be no more than a 3 hour job, knowing what I know now. Steps include:
1) Chock all the wheels for safety (front and back of each tire). I have had a car slide off a jack, and it is worth it to chock it properly. Jack up the car and in addition to the jack put a jack stand in place for added safety. If you don't have a jack stand use concrete blocks or anything that could potentially take the weight of the car if it fell off the jack. Remove wheel. Spray bearing hub bolts with PB blaster.
2) Remove caliper and rotor. I used the bolt and nut on the upper caliper mounting hole trick to pop the rotor off since I wanted to reuse it. If you are replacing the rotor then just beat the crap out of it and it'll come off.
3) Remove cotter pin and axle nut. You may be able to pull the hub off but I had to use the gear puller to grip the edges of the 5-bolt hub and put the center bolt on the axle - there is a dimple on the axle for just that purpose. Once loose, I was able to pull it off easily by hand.
4) Now for the fun part - you have to reach in behind the axle carrier/dust shield to remove the four bolts holding the bearings in place. My bearing was so shot I could push the outer CV joint aside enough to reach the bolt heads. Or like Infinitifan25 suggests you can also push the axle in enough to get at these; my experience on reassembly showed me that works just fine. I had to place the socket on the bolt head first to clear the outer CV joint, then insert the extension and the breaker bar. I could not put the socket on the bolt head with the extension in place - not enough clearance; it is a two step process. Use a length of pipe on your breaker bar to give you leverage to break the hub bolts loose, then use the ratchet driver to take them out.
5) If there are any bearing remains on your hub, you can CAREFULLY cut them off with a dremel and cut off disks, or better yet use a bearing remover like 06FX35 suggests above. OR, take it and the new bearings to a friendly machine shop and have them remove it with their bearing puller and at the same time press in the new bearings.
6) Fit the new bearings and hub back onto the axle carrier, reach behind and put those four bolts back in. You will now need to push the axle shaft in to make enough room to reach the bolts with the new bearings in place, but I found mine sufficiently recessed that I was OK.
7) Put rotor back on, remount caliper and wheel, and you are done. It's that easy.
This cost me over $500 with parts to have a shop do it last time, hence my motivation to source the part on my own for $150 and mount it myself. If you have a high priced Infiniti shop you could be looking at $750 easy. They charge a ton because the official Infiniti shop method dictates removing the entire axle carrier, meaning lots of tough bolts and a ball joint. Sure, this makes it super easy to get at everything, but you risk the damaging the fragile speed sensor ($200 alone) and it takes a TON more shop labor which means $$$. My opinion: You don't need to take it to a shop - do it yourself. Good luck!