All told, this took approx 6 weeks between the start of the project and when it was finally, completely working. If someone had told me at the beginning that it was going to take 6 weeks to exchange a HDD I wouldn't have believed them. A lot of the time was waiting for the postman to arrive with more parts...

First, pics of the inside of an Infill G4 for anyone that is considering their own projects:



My G4 was one of the originals with an IDE drive installed. What is pictured below is the Marvell 88SA8040 SATA-to-PATA bridge chip, which means the white header to the mainboard must connect to a VIA SATA port.
Instead of purchasing an IDE-to-SATA board, which made no sense to me as the white connector has SATA, I decided to solder SATA data and power connectors directly to the white connector. Why go SATA->PATA->SATA when you can go SATA directly? This means that I had to disconnect the Marvell chip from the SATA Data lines from the motherboard. Instead of using a hot air gun to cleanly remove the chip from the PCB, I decided to Xacto the lines. I'm not going to need the SATA-to-PATA bridge anymore anyway, right?
I got the pinouts noted on the first picture below from this webpage.



The first hiccup was the metal support beam in the upper right of the picture interfering with the newly installed SATA cabled. Out comes the dremel with a cutting bit...and the offending support is disappeared!



The SATA Data and Power lines are routed and ready for the SSD



Now to try the SSD...hmm the computer seems to hang.
Reboot, hang, reboot, hang, reboot, hang, reboot...SUCCESS.
Now to install windows...drive not detected?
Reboot, hang, reboot, hang, reboot, hang, reboot...SUCCESS.
Now to install windows...drive not detected AGAIN?!
Lets try with a normal SATA HDD instead. Hey, this seems to work.



Windows installs successfully with a standard HDD, then why doesn't the SSD work?
After some sleuthing on the 'net, it seems that when VIA developed the CX700 they "cheated" and optimized the chipset assuming that all SATA devices would be slow. This means that they send the "startup" command then start processing other interrupt items for a few milliseconds before coming back to the HDD and waiting for the "drive ready" response. This works wonderfully for slow mechanical HDDs and Optical drives, however SSDs send the "drive ready" response almost instantaneously. This means the chipset misses the "drive ready" response the majority of the time.

The only way I could think of fixing it was by putting a different SATA controller behind the drive to act as a buffer between the SSD and the CX700 chipset. Initially I looked at an SATA port multiplier, but the cheapest ones cost almost $100. Then I remembered that the Infill initially came with an IDE bridge chip that I so carefully bypassed. An SATA-to-IDE adapter board costs $4 on DX, so back I go to repairing the IDE board.
I broke off the B+ pin when lifting the pin from the pad initially, so I had to scrape away some of the packaging to be able to solder to the remaining pin. (The red and black plastic to the left of the picture is from the SATA Data and Power lines that were glued down for permanent installation...)



Now that the SATA-to-PATA bridge chip is reinstalled, time to try the SSD again...SUCCESS! FINALLY!

The SSD works beautifully. Streetdeck is ready to rock 28sec from a cold boot, this is less than half the time from the mechanical HDD. The real beauty of it to me is no longer having to worry about having a HDD in the unforgiving car! -40C here some days, HDD bearings don't like the cold.

For those of you with a newer Infill G4 which came with an SATA hdd, I am assuming the process would be similar, with the difference of purchasing 2xAdapter boards, SATA->PATA and PATA->SATA then connecting them back-to-back. This may add a bit of latency, but the G4 isn't a performance machine to begin with, so I was prepared to deal with the tradeoff for the added benefits of the SSD.

If anyone is still using their Infill G4, I hope this answers some questions about installing an SSD into your own.