[hardhatz]

Just my humble opinion....

Congratulations on some very nice work!
It is particularly impressive that someone who doesn't care to drive them would put all this effort into such a huge undertaking.

Some thoughts:

1. Big rig fuel mileage strategies that rely too much on hypermiling tactics are only entirely relevant when time stands still and the world is flat. In real life in the business of trucking, there are many aggravating factors. For example, one MPH less speed adds an hour to a coast-to-coast run. So, if you arrive at the other coast on Friday night after the receiver closes for the weekend, you have just shot yourself in the foot. If-by driving 65-you arrive Friday morning, and reload back out the same day, you could be 2000 revenue-earning miles away by Monday morning. This is not an isolated example. I drive, it happens all the time.
Focus on the technology. Getting 14 MPG under ideal and atypical conditions is interesting, but there would be a lot more credibility if you also included real-world numbers.

2. Congratulations on running a 13-speed! The industry has really drank the Kool-aid on the Big 9 & 10-speed Lie. It's a hard cold fact that the lowest BSFC on an engine is only about 150-200 RPM wide.
However, most 13-speeds are RTO. (I'm assuming yours is as well) RTOxxx13's are overdriven in 13th, and trucks are usually geared to cruise there. 13th gear loads torque onto six gears, 2 countershafts, and several bearings. Only in 12th does the torque path run from input to drive yoke uninterrupted. RTOs should be geared to cruise in 12th. Don't feel bad, about 99% of rigs were built wrong, and the average new-truck sales guy is a blithering idiot.

3. The electric drive idea will not be efficient. The driven motor is most efficient only at a certain RPM. Locomotives are built with different gear ratios, based on expected use. They are significantly disadvantaged anywhere outside that ideal speed. To be more specific, the Diesel/generator must be operated at full capacity even though the driven motor may be turning at a small fraction of its efficient RPM. So, your engine-to-wheel RPM ratio goes completely screwy, and you are under full power. Once again, if the world was flat.....
If you are in love with electricity, use it to replace the hydraulic in the power-steering.

4. Consider radical redesign of suspension, as all vertical motion/vibration caused by road irregularities devours forward energy. Independent maybe, with bus-type IFS, and DeDion-type rear?...

5. How about an air-bagged front end to regulate front body-to-road gap?

6. Axle stub-mounted non-rotational front wheel fairings.

7. Charm the rolling-stock folks into building a "1 1/2-plex" low-profile front tire/rim system. (halfway between a single and a duplex) About 8000 lb capacity.

8. Centrifugal engine oil filter to keep oil free of abrasive particles.

9. A single-screw with tag axle does not provide the integrity needed in any but ideal situations, and I consider it cheating. Keep it honest.