Hi Jules,
Yes, that is correct. In fact it is one of the main features of Qimage and part of the reason it produces great prints, even from low resolution images. QU also down-sizes for small prints
Linked with the re-sizing that Qimage does is its superior re-sizing algorithms.
So in answer to:
Definitely no! Muliple resizing will degrade an image.
QU re-sizes to the "native" resolution of the printer, eg. 720ppi for Epson, 600ppi for Canon. This avoids the driver "messing up" the pixels.
You can see the reported printer resolution from Qimage above the page preview - the numbers in brackets.
Yes, just select the print size required in QU & put your original image into the queue and print.
I hope that is clear, if not please come back.
The web site has a lot of info'
http://www.ddisoftware.com/qimage-u/quality.htm
http://www.ddisoftware.com/qimage-u/technology.htm
Terry

You could do this in QU using Tone Targeted Sharpening: select the tone that needs softening and use a negative percent value to soften; TTS can be set to sharpen the remainder if required. There are several other options and tricks too - I do all my sharpening in QU. 
Just to satisfy myself, I printed a crop of an image to get 180ppi, see attached a screen shot of the page editor with full size and crop of the sample image.
I thought that at normal viewing distance, the 180ppi print was very good. I'm sure you'll get a good result too. Make sure you have "Fusion" set as the interpolation method.
Terry

Ok, so I've talked them out of using that image. They're looking for another one instead but it would still be good to know...

Thanks Terry,

55ppi is ridiculously low in fact, no need to be polite. When testing the different interpolation methods via 'print to file' I found that with a really low quality image, using fusion there are so many invented pixels that it just becomes too smooth, there are some others that look similar to pixel resize (can't remember exactly) that are obviously too blocky, but somewhere inbetween would probably look the best. So knowing it'll send it to the printer at 90 or 120 or whatever will be an experiment worth trying. Thanks for mentioning the 'finest detail' button, I'd forgotten that was what gets me 720ppi.

cheers

Jamie

You're right Jeff, figured that out after I did a couple of test strips. To my eye they all looked identical so... Using different interpolation methods are the way to go, though I don't plan on trying to print anything that bad again, but still good to know.

Thanks again.

Jamie