Hi Lisa,
That symptom list is really interesting. I have (or have had in the past) nearly all those symptoms, excluding only gait problems, Extremely deep skin "dents, Feeling of skin being burned and Veins pop out of skin (look "ropy"). All the others, I have had.
My doctor attributes the petechiae and all these symptoms to bartonella.
He says bartonella reproduces under the skin and every 5 days, then migrates into the body (you don't really feel this 5 day cycle symptomatically). It can cause devastating neurological damage. His list of the most classic symptoms are peripheral nerve damage (ranging from numbness in extremities, to loss of coordination etc), petechiae or a rash that looks like "stretch marks", itching that moves randomly around the body, joint problems in the knees and ankles (pain and/or squelching noises as you move), feeling freezing cold (with very cold hands and feet) even in warm environment, swollen lymph glands, night sweats and day sweats too, severe cognitive dysfunction (at first onset I completely forgot how to speak or understand people) and sometimes neuropsychiatric disease which can be depression or can be as bad as schizophrenia. All the other symptoms on your list are horribly familiar to me, including convulsions for which I was hospitalised a good few times, and the inability to find my way home, from which I still suffer permanently (I have to make sure I have the sat nav every day when I collect my son from school because sometimes I get lost on the way home. Luckily he is 6 now and is starting to tell me the way to places himself).
Bartonella is spread by ticks, fleas and mosquitoes. It can have an acute onset with fever etc, or start gradually and insidiously. There are many different strains of bartonella which may explain why it has two types of onset and two types of rash (that is my speculation not something I have read). The way it is disseminated could certainly explain why it sometimes occurs in isolated outbreaks and sometimes breaks out as a mini-epidemic. Apart from the famous Lake Tahoe epidmic, which I think could have been bartonella, there have been other similar outbreaks like that in other places.
The petechiae that I have are nowhere near as severe as the ones in the photo in the Wikipedia article. I think that article is not very helpful in the sense that it lists all possible causes of petechiae, but does not explain that different illnesses case them indifferent parts of the body and with greatly differing severity. The ones I have are mainly on the torso but also on the arms and legs. They are about the size of pin heads (some the size of metal pins, and some those larger glass-headed ones). They are all separate, there are no places where a bunch of them meld into one patch like in the Wiki photo. I got a particularly rapid increase in them on my torso when I was pregnant.