Hi there!

It's an amazing trip! Ride Far has given the most pertinent info on your other thread here: http://www.horizonsunlimited.com/hub...ethiopia-95124

On a different forum I wrote a detailed report, which you can find here. Part 1 covered the entry problems people were experiencing for Ethiopia and some other background info, for your part of the trip, these paras are the interesting ones re passport and carnet stamps outside of Nairobi:

... We dashed off south to Eldoret to get our carnet and passports stamped. It was extremely fortunate that when the Head of the Revenue Authority had replied to my email enquiry he had included the right team in Eldoret, because when I got there, they were all out at an external meeting and the junior of the team told us our request was impossible: the vehicle has to be viewed on the day it leaves the country. When I said I'd spoken to the Head, including his name, he raised his eyebrows and asked us to sit down. An hour or so later he stamped and signed our carnet after kindly calling the right people and they told him what to do.
Another strange situation at the passport office when the department head said there was no need to stamp us out, as our permitted time in Kenya expired in a couple of weeks, despite our East Africa visa being valid for another 6 weeks. He told us the border officer must have been rather inexperienced as he would always stamp tourists in for the maximum allowable time. While we found this all a bit strange, we were happy not to have a stamp in case we arrived in Ethiopia and they were still demanding huge, unaffordable deposits for entry.

In part 2 I noted down kms and timings and quality of road:
Up the east side of Lake Turkana (Part 2)

If you need any other info, just let us know!
Hope you have a great trip!