Kirk,
I just went round and round on this subject for about a month. I originally planned to use the new PTHD192 I/O as a front end converter to digi001 until I could afford the full upgrade to PTHD software, then found out that this new interface will only work with PTHD software and can't be used as a standalone converter. Another shot in the foot for digi.
Then I wanted to either upgrade to PTHD or look at buying another third party converter that would compare to the PTHD converter at 24/48k. I came across the Prism and Cranesong HEDD192. I ended up buying the HEDD192 for around 2,700.00 from http://www.soundpure.com (Todd). I'll let you know how it works out here, but the reviews I've read on the HEDD192 from people on this forum are nothing short of incredible.
The cost to upgrade to PTHD192 with software would have run around 10,000-11,000 dollars after selling my digi001. A little more than I want to spend right now. The big question is, for someone that doesn't require over 24 tracks, can you get just as good or better quality as the PTHD system with this kind of setup? If nothing else, it will make a great addition to the Nuendo system on a PC.
Allen :)

Thanks for the reply Allen. The HEDD was one of the converters I was strongly considering. Let me know how it works out with the Digi.

Another one worth considering is the Benchmark converter.

well, i got to agree with angelo for what i've heard--the D/A benchmark stuff is killer.

also: check out lucid, cause it's VERY reasonable [just over 2,000 or so for the 8 channel one].

and lil bit of knowledge:

the cranesong spider has really 10 hedd a/d converters in it [8 channels + stereo bus].
it's 7,500. + pres, limiters, tape emulation, dithering...
and this is the killer: he's gonna make a d/a expansion module.

get in line kids. save yr pennies.

check out the hedd, but if you want 10 of 'em, and 8 pre's for free....

plug that into yr protools rig and smoke it.
--owen

I wish I had the dough for any of those!