I am using 2 TM-D1000s in my studio. Once you learn your way around them, they offer a lot of routing options. Unfortunately, Tascam doesn't sell any of the add-ons (the extra digital card or the rack ears) any more. I bought a set of rack ears for my first one, and had a set fabricated for the second (they cost me $30 at a metal-working shop, vs $57 from Tascam, when they sold them).
Tascam sells the TM-D1000 video at their online store for $20.
Instead of using a sound card with a TDIF connector, I use a Terratec EWS88D with ADAT lightpipe fiberoptic I/O. It requires a Tascam IF-TAD converter box to change the format. It has the advantage that you can run much longer cables. Tascam limits the length of the TDIF cables, which makes it difficult when you have the computer in another room for noise reduction (as I do).
Using the TDIF cable out, you can set the channels for "Direct Out" and that gives you 8 simultaneous outs. Using analog outs, you are limited to 4 buses.
Although the mixer only has 4 XLR inputs, I have a stereo mic preamp patched into channels 7-8, and I am planning to get another that has S/PDIF outs to patch into 5-6, which will give me 8 mic inputs. Meanwhile, I can run a drum machine or a synth into the second mixer's line ins (channels 5-8) and then route THAT into the first one via the AES-EBU digital ins (this is where you need the extra digital input card: you can't use the S/PDIF and AES-EBU ins simultaneously). At the same time, I route the main outs from the first to the second mixer via AES-EBU and use the second one to drive two headphone amps and the room playback speakers (the mixing monitors come out of the first mixer's main analog outs).
The main drawback, aside from the limited number of XLR ins, is the 48kHz sampling rate, but, since I'm burning everything to CD anyway, it's no big deal.
One tip: don't yank on the power supply cord! The input for the power supply on the mixer is pretty fragile, and after paying a $50 bench fee to get one soldered back on, I attached a loop to the rack, wrapped the power lead around it and tied a knot, leaving some slack between it and the socket, so it would act as a strain relief.
on Ebay, should be here any day. Now I get to use all 16 channels in and out. I bought and installed XP last night.