When Justin gets the Snake Anchors in I'm going to order one, but only so that I can have a dedicated base anchor in the kit, I've been using a length of ordinary semi static to tie off with up til now and it's fine. I prefer the idea of knowing that I'm hanging off something which has only been used for that purpose and it will shorten set up times even further.
As Paul says though, it's not an essential part of the set up, it's icing on a cake really.
The thing which I found makes the biggest difference is getting your feet working properly. If you already have an efficient frog walking set up then you're nearly there.
Someone pointed out in the RW thread that it's all about 'little steps' and I've found that to be spot on. You don't need to be taking massive strides up a rope to begin with. So long as everything tends smoothly you will always ascend quicker than DDRT.
I have my line hanging up from a rafter in my shed so I can tinker with my set up at leisure, it's made a huge difference, to be able to experiment with different arrangements in my own time.
The wrench is a really nice shiny descender, but for me the biggest benefit of SRT doesn't come from the wrench, it comes from 1:1 ascent using mechanical ascenders.
The wrench just means that I don't have to change all the kit over to come down, just uncip the croll and pantin and I can then do the cutting and come straight back down. In that respect it's very similar to spiking up a spar and having a choked single line and figure 8 for fast descent.
In fact, have you considered the 'Fate [F8] Revolver' system as a first step towards a wrench? Here's Kevin's video, he really is a pioneer of SRT....!
[ame=http://www.youtube.com/watch?v=XyXwrXgN0qw]the F8 revolver - YouTube[/ame]