Thank you so much for the analysis. This has helped me a lot in plannign things out and I'm sure will answer questions in the future for people.I will say this about the Fusion Brain Control Center Uber MDX: it is definitely not designed for the low power, min memory legacy computer. My ST3500 has 500MHz processor, 256Mg memory, full XP Home (but not SP2), daylight-readable transflexive touchscreen, with one onboard USB and two more in the dock. I had tweaked this system for years to get a stable platform for RR, Freedrive, DIVX playback, and Internet radio. With everything running and all above USB connections the CPU usage averaged 80-90%. To install Uber MDX, I had to update XP to SP 3, load .Net 3.5, and give up an additional 800+Mg of diskspace. The drivers had to be manually installed as well as the RRFusion. Trying to install Uber MDX without the above crashed everytime. RRFusion was pretty straight-forward although since I'm a skin junkie I had to put the fusion setup strings in RR.ini so it works with all my skins.
I talked a little about my hubs above and my signature tells you almost everything about what I'm running in the cars. While waiting for the attendees of the St Louis Mp3Car Meet I opened up my car and attached my Fusion brain to my ACC power block. The ST3500 Tablet for this experiment was powered by a cigarette adapter power supply which may somewhat skew the results but most of the experiment was done while the car was running so the data should be accurate.
With nothing else hooked up other than the FB, it worked like a charm - no difference from USB 2.0 systems. As soon as I connected thru my hubs things got interesting. Response time for a digitally triggered relay using the direct connect with nothing else was appx .3 sec at 50% CPU and all sensors active. The same signal thru the hub with all other accessories took over a second and CPU hit 95-99%. My setup has all sensors active but only two temp sensors were connected. If all sensors had been connected I feel sure in saying the bandwidth of the USB 1.1 would be maxed out completely. I vaguely recall something about adjusting the refresh rate on the analog inputs - that might help some, but the more gets added to the hubs the slower it AND EVERYTHING ELSE CONNECTED THRU USB gets. You can forget about USB DVD or Internet Radio and GPS routing falls waaaay behind.
The bottom line - YES IT DOES WORK!!