Why would MD want to add an AGP port? After all, their "Lightning+" is surely the best thing since sliced bread? And what would be a possible timescale for both RO Ltd. and MicroDigital coming up with a solution? 3 years? At the moment, the chipset solution that is available from MicroDigital, which took 4 years to develop, is severely underpowered compared to "off the shelf" components available and used elsewhere. I see no reason why this should change in the future.
Anyway, I agree that it is very unlikely that anyone provides us with an ARM chipset along with an AGP port. However, it is important to know that the PC market is moving away from AGP anyway, and its successor PCI Express looks to be very interesting to the Intel side of the ARM market - after all, there are already Intel PCI bridges available for PCI Express -> PCI-X and PCI bridging available, so I consider it very likely that future XScale I/O processors come with PCI Express.
The reason why the IYONIX pc is still comparatively expensive to a PC is down to the lack of a large production run and the size of the market. It is not down to component cost. Is the comparatively low price of the IYONIX pc down to component cost of the Omega?
And speaking of PCI graphic cards, it is actually still very easy to obtain them for very low prices. Matrox (Millenium G450), nVidia (GeForce 2 and 4) and ATI (Radeon 7500, 9200) will be happy to provide you with anything you might want. I am not sure why you think that they are either expensive or hard to obtain - even your average box shifter still sells them.