I bought a Neo cross last September and immediately started breaking spokes.
Been through the whole rebuild business several times, and have come to the following conclusion...
The problem is one of design. The Neo motor has spoke holes that are counter-sunk on BOTH sides, leaving the spoke elbow unsupported. This allows the spokes to flex, work-harden, become brittle, and break. They don't need to flex much, but they get flexed about 800 times a mile, 120,000 times a week - it all adds up.
My best solution so far is to place 7BA (NOT 8BA) brass washers behind the the head of the spoke. This pulls them into the hub and reduces flexing.
This is not a new solution. Its mentioned by Sheldon Brown in his article on wheel building. However, most bike spokes are 14 Gauge, and use an 8BA brass washer. Electric Bike spokes are normally 13 Gauge and require a washer with a bigger hole, so 7BA. Don't buy from a bike shop, you need to try a model shop. I get mine from Macclesfield Model Engineering at about a tenth the cost of a bike shop.
Spokes - Sapim Strong, DT Swiss Alpine or Alpine III. If you use DT Swiss they are supplied with nipples that are not designed to allow much of an angle at the rim. Saphim Polyax nipples are much better (read on!)
Getting the washers behind the spoke head is a struggle. You need to pre-dish them. Find a thick bit of metal - an 18mm bolt is good enough - and drill a 3mm diameter hole about 10mm deep, next use a 7mm drill to drill a couple of mm into the 3mm hole, effectively counter-sinking the hole so that it looks like one of the spoke holes in the motor. (The measurements are not critical, I just happened to have the bolt and drills in my garage. The 3mm hole is just to stop the punch hitting the bottom of the 7mm counter-sink)
The 7BA Brass washers can now be placed into the hole you have just drilled and with a light tap and a centre punch or phillips screwdriver, can be dished. Now these can be place on the spoke before it is threaded into the hub.
This will shift the problem to the other end of the spoke (At least it did for me). If you look at almost any eBike motorised wheel, you will notice that there is a bend at the nipple. As with the hub, this end will flex and break. Why it doesn't - I can only assume it is ok in most wheels, but mine started snapping.
If you rebuild using standard bike spokes, listed above, the nipples are slightly smaller than those used in the bike as it is supplied, and with the polyax nipples there should be enough space to allow a fairly straight entry. If you are lucky enough to get some spokes out of BH (rocking horse s**t is more common) then gently filing the holes (don't drill, the holes will come out triangular, best to get a reamer. If you don't know what this means, a file is just fine).
If you want a really professional finish, contact Team Hybrid. They have some really nice rims which are dimpled and drilled at an angle specifically for big hub motors (and while you are there wonder why you did not buy one of their Falco conversions - Dear Santa...)
By the way - DO NOT use eyeleted or double-eyeleted rims! They are great with a normal hub, but with the diameter of a motorised wheel they will not allow for the necessary entry angle for the spokes.
I cant say for certain that this is going to solve the problem. I weight 150Kg and commute 30 miles a day on my bike. So far I have managed to travel twice as far as ever before without breaking a spoke. The only one that did break (On my second run) with the above design did not have a washer behind the head (Which is when I came up with the dishing idea)
If this fails - contact Central Wheel Components - they sell car spokes. The biggest problem is that if you end up unzipping the rim with the big holes you will need to get the nipples through.
If this does not work - then I have a cunning plan!