I've integrated KCS traceme products for vehicle track and trace. The devices I used are being resold and re-branded often. Their product is called traceme (as a google keyword that sucks a bit).
These are highly configurable and also programmable with a configuration, a firmware (gprs uploadable) and what they call a source lcd menu combination.
If you don't buy them in lets say, quantities of around 500 you need to go through a re-seller. We currently use Streamline (Netherlands), also as our technical contact point. As you notice, they are re-branded. Another party that sells it (to demonstrate the re-branding) is Fleettronic (Belgium) which used to be our channel.
I think there are a dozen of these, and they are internationally available. Of all the units (starting in 2006) we evaluated technically to build a platform around at the time, this one was the most versatile and of another breed as the competition. I work for Synctrace, which matches my LinkedIn info, in case someone thinks I'm overly enthusiastic about this.
It's been a good 6 years now, and although hardware always needs to be followed up, the speed of innovation and also the technical request we made in the past, if they are feasible, they get implemented in time. Which sometimes is crucial to be able to win a project.
What I find to be the most interesting software features, is the fact that we get a readable class to parse incoming data but also a class to control the configuration of those devices starting from a (.tms config settings file) template. so you can change target IP's, timer settings. Event config changes. This enabled us to create product lines around it, controlled by software.
To specifically answer your question, since we have around 3000 of these units under our control, making them talk with a webserver is a serious performance problem. Hence we wrote our own backend tcp server based on their proof-of-concept server implementation (which is available on the BETA link site).
I used to have a direct channel to the developers which helped a lot at the time, but when they became too successful, they put in the middle men.
The devices are truly flexible, the firmware is compatible with all units in the same range (Revision: 5, 8, 9 and 10 is coming). But they have micro units as you can see on the site, the firmware that goes into a big model can also be uploaded to the nano. I know that in South Africa they have the nano (2 of them) built in in Rhino's, 1 in the horn and another somewhere at the shoulders. Just to try and keep them alive. People do all sorts of wicked idea's with it.
Most latest firmware's are right now around a 150k. The config is very small, a few thousand bytes and every raw event you get back is 33 byte in size. which is without the leading IMEI number and the http overhead. The .src file (programming) is depending on the content in between those.
Keep an eye open for units alike, they all come from KCS manufacturer with no hardware diff at all. so prices vary as well.
Hopes this helps finding the right hardware for the job.
In case you want some configs, you can download their executable(windows) -but works on wine (linux) too- update: they took the programming software/firmware download offline, you have to ask a re-seller now. I can still share some configs that work with a full battery for 6 months, live tracing, anything in between.... results of weeks of R&D. They used to have Alkaline models too (vs. li-ion models), not sure if they still offer those but we use a large (6-cell li-ion) battery now in combination with power saving features to reach live-event-based tracing info (so NO timer, but based on cornering, distance events or sensor events like acceleration/vibration, gps) and that works for 4 months so far without charging.
A timer of 1 sec will clutter your map btw, you want start/stop/direction/distance events to build a track. You will also drain the battery with the gsm (gprs) since it will be on all the time. But if you're smart you can tackle that with events. Your queries will run faster too as you have less data to analyse.