I would like to echo some of the comments up-thread. Scribus is a desktop publishing program first and foremost, and not some kind of effects package. Classically, standard desktop publishing programs (and my memory is long enough to stretch back as far as Springboard Publisher, Aldus PageMaker, etc.) have relatively limited ranges of effects they can apply to type, the idea of which being they are designed for layout functionality, and doing all kinds of stuff to type falls much more under the heading of graphics software. I know that in more recent times, Adobe InDesign has somewhat blurred the lines here, but even it has its limits, and requires one to use other software, like Photoshop or Illustrator, etc., and then one can import that object as an image.
I'm not per-se against Scribus having extended graphical capabilities. There are times when it would be nice if it also did some of the stuff InDesign does, but I'm not going to ask Scribus' developers to turn it into another iteration of, for example, Inkscape.
Now, all that said, I'm also old enough to remember some utility software we used to have in Mac OS which would do type effects by way of taking the initial text you were interested in (for example, a business name) and parameters of what you were interested in doing (drop shadows, mirror reflections, etc.) and then sending that to a network-attached, PostScript-capable laser printer for rendering, and then returning the finished data to the user as an image which could be saved as an EPS or a TIFF. (Yes, I do go back a fair bit...) I also remember latter generations of that sort of graphics utility software being able to apply the effects through local processing (i.e. on the computer you were using) because by then Adobe had released PostScript to the extent that others could make use of it.
Getting to the point raised here originally by eudoxos, I would think the best-practices way to do what you're trying to is to use Scribus to set the initial text you want at a large enough size that it will be easily worked on by you, then convert that text to outlines, export that page to SVG and open it in InkScape, do whatever it is you want to do with it and save it in there, then import the resulting object back into Scribus and place it into your layout however it is you see fit. That's how I would do it, anyway.