Well the reason you can only get 8 bit DV25 from the SD Connect into Vegas is well, the fault of Convergent Design. We have two of the boxes and they do earn their keep but mostly going the other way around, 1394 to SDI. Some systems do not have the ability to capture via 1394 so you either need to buy a very expensive DV deck with SDI or use something like the SD Connect.
But I've got to agree with you, I too am pretty unhappy with the amount of time it's taken them to get the drivers written but they claim the cause of the delay lies with Sony.
What I've done is buy the poverty pack BMD SDI card, not what I wanted to do as I was looking longingly at their Multibridge Extreme being connected by PCI-E but it's not quite ready yet, when it is I'll probably plonk down a lot of cash for it but I like you needed to get DB into my system pronto.
So what I'd suggest you do is look at getting a BMD card and you're away for not too many dollars. To be honest now that Vegas supports these cards (well so we're told) I cannot see much reason for the SD Connect unless you need to capture from component inputs and even then you only need the appropriate BMD card.
As to the 8bit / 10bit thing I've got to admit I'm mighty confused. I'm reliably told that DigiBetacam is only 8 bit! Sure you get 10 bit data down the SDI cable but there's two bits of nothing padding it out, same source tells me this is a great con job by Sony so maybe that's why Madison never seem too worried about not having 10bit 4.2.2 output as it wouldn't make much sense if the input was actually only 8 bit! However I see you're coming in analogue so I guess the BMD card does do a 10bit conversion.
All that's quite different to the 4.2.2 sampling issue though. I must say I've not seen a huge quality boost making a DVD from 4.2.2 YUV compared to 4.2.0 DV but I'd imagine if you're in NTSC land things could be quite different.
The other thing I'm pretty unhappy about is Madisons complete lack of support for anyone using the BMD cards. The manual has nothing specific to say and tech support is plain asleep at the helm and I'm left providing tech support to local Vegas users who've spent very large sums of money on hardware to run Vegas. It's all well and good SPOT, myself and others sharing our knowledge but why should we have to do this? It'd take those in the know only a few hours to pen a Whitepaper for the knowledge base. That would have saved one local production house weeks of lost work and significant loss of face for myself and their engineers.
And I did note one reply from Sony some time ago, they suggested we should talk to BMD, well yes I did, maybe I shouldn't repeat what they had to say in an open forum.
And this is before I even try to figure out just how we're meant to PTT via SDI!
Bob.