It looks like you found the same USGS Europa base map I fought for a while. Wise move not showing the longitudinal strips of high-res mapping (which fall just to the East of displayed section).
The best solution I found (so far) was to simply use a gausian blur to 'down-sample' the high-res material to the 'medium-resolution' of most of the map (which is still superior to Voyager era imagery), scale down to 4k, and then apply a reduce contrast filter to sections that were stilll glaringly ugly. At a distance, it was okay, but close up it was still very ugly.
The big problem, is that unlike Clementine or Mars orbiter mosaics,
the high-res images for Europa come from Galileo passes at rather different altitudes and illumination angles. Some of the high-res segments were illuminated at a low angle which makes them look far 'bumpier' than the rest, and I think this was exacerbated by some image processing done by the USGS. Definitely not made with computer rendering in mind.
I'd note also that your rendition has far more contrast between the ice plains and reddish soot than I've seen in either Voyager or Galileo full-color image. Judging from how much the color calibration changed between Voyager and Galileo (eg, see the old bronze vs. the new bright yellow Io), I believe all Voyager color composites should be viewed as suspect, and are at the very least oversaturated on the red filter.
That said, I like the following image of Europa from a purely aesthetic standpoint, and used it to guide my own coloration decisions:
http://www.solarviews.com/raw/jup/europa1.gif
Others are even less red. Perhaps most telling are the color images of Europa passing before Jupiter's disk. Regardless of how saturated the Jupiter coloration in the color composite, Europa, even its dark hemisphere, is lighter and less saturated in color.
Some other considerations: the reddish 'soot' doesn't always follow the 'cracks', and in some high-resolution images actually appears as though someone sprinkled powder roughly, but not exactly, along the path of the surface 'cracks'. So just colorizing based on the monochrome image isn't correct. The dark 'cracks' aren't even neccessarily the largest or most recent, just the ones that coincided with a historical episode when the crack formation coincided with some outgassing. Or so it seems from the detail.
The darker 'cracks' don't correspond to canyons, in fact from oblique illumination images the surface is a very chaotic patchwork of very slight ridgelines from multiple episodes of cracking and reannealing, at different overlapping angles. The dark 'cracks' aren't even neccessarily the largest or most recent, just the ones that coincided with a historical episode when the crack formation coincided with some outgassing. Or so it seems from the detail. Any bumpmapping based on albedo features seen at the level of the medium resolution material of most of the USGS map is fairly deceptive.
As an aside, some of the Photoshop/mosaic work of Michael Benson in his book "Beyond: Visions of the Interplanetary Probes" is very, very impressive. A reasonably priced coffee table book that has some more unusual selections from the JPL archives. Some filler, but the high-res hemispheric mosaic of a Martian dust-storm is alone nearly worth the admission.
Anyway, I'll post my 4/8k Europa when I get back from break on 1/2 or so. I still prefer John Van Vliet's Europa, for even though it pales a bit in color accuracy and resolution, it is free from the glaring rectilinear patches of high-resolution/low-illumination angle patches of the USGS map. One solution I've considered is to substitute the Voyager era material for these patches, but suspect the problem would simply be shifted around. Perhaps in 2010 after the JIMO mission we'll get the Europa we want.
After finishing Jupiter rings i decided to try to find some new textures for the galilean moons and i am starting with Europa. This texture is made from several photomosaics i found over the net and using copy/paste to join them. For now it looks like this:
arkmiss
hey I take it all back...... 
