Does anyone know if it's possible to buy east Africa visa at the land border crossing between Tanzania and Kenya? I would be very grateful for the information.
I do not know the answer to your question. What I do know is that Kenya is stopping visa on arrival from 1 Sep 2015. So from 1 Sep, I doubt you will get any visa at the border.
I too don't know the answer but two days ago I applied last week for EAVISA on line through lusaka and was given full confirmation by email within 2 days. Very efficient... Expect if you have the visa you will get it??? Note you must get visa from country you are arriving from.. since I am in Zambia I applied in lusaka embassy.... they then send you a full copy of visa etc etc and you pay on arrival... good luck

Travellinandi: thanks for the answer, did you aplly for the EASVISA at Kenya embassy in Lusaka? I will be in Tanzania by the time so I could easily pick it up in Dar es Salaam but of course there is lack of information on that topic at their website

By the way I found information from February 2015 saying that Tanzania has joined East African Community and now it's involved in EAVISA but I'm not sure whether it's true or not

Well I found the news in here http://www.cnbcafrica.com/178574.aspx so I thought something might have changed