It should launch alone without any macports environment, may
immediately kill the X11 after its launch - and makes a quite useable
impression.

Why not completely remove the part that launches X11 (what if the user
has other x11 apps running and needs to save data before quitting X11)?

You are very wellcome to tell me a less brutal solution. Unluckily I dont know the place where the X11 launcher script is called - and how I can abandon it.

It was made on a PPC, 10.4.11. Unluckily I cannot switch to the
universal variants at the moment, so I'd be grateful if some intel
owner would check whether it runs on rosetta. I manually removed i386
python components, this may cause intel machines to get in trouble.
Also, I couldnt check whether it works on Leopard or Snowie…

Summary:
Inkscape 0.47 Tiger PPC Quartz fails on OS X 10.5.8 Leopard i386 with
the same error as your other build (0.47 Tiger PPC X11) on Tiger and
Leopard Macs with Intel architecture (see related bug reports #513335,
#517883, #520022)

Bare in mind that it is NOT an universal build - it's PPC only. IMHO there is not much of a clou to make the whole thing "rosetta proof". Rather we should go for a native intel build - probabely less effort and a much better result.

fails when I try to invoke the +universal variant - and the author of the patch doesnt have an idea what's going wrong with it. But building an intel version from scratch should not really be difficult - as even I could do it on the PPC side.