I've been using and loving the modified version of the Sphax 64x texture pack put up by leddy231 (in this thread here: http://forums.technicpack.net/threads/64x-sphax-purebdcraft-tekkit-3-1-technic-7-2-balkoons-weapons.910/).
The only textures I didn't really fancy are the Solar Arrays in the pack - the basic Solar Panels look awesome and techie but the arrays use the side textures from the EU storage packs (see the textures of the boxes holding the signs in the screenshot below for the old styling).
I've modified the Solar Arrays to have a styling similar to the basic Solar Panel, with some differences to differentiate them from the basic panel, and from each other.
I believe this is when a screenshot would be sensible!
What I've done:
I've left the basic panel as is. With the three arrays, I've used the grey metal border vs the bronze metal border of the original - the grey metal border is used for the more advanced generators such as Geothermal and Nuclear, so I figured it was appropriate for these powerful (and expensive!) arrays. The panels are coloured copper, gold and diamond for the LV, MV and HV arrays respectively - this matches the colours of cables for the respective voltage capacities also (think glass vs HV cabling for the HV array, making a iron coloured HV array was underwhelming).
What you should do:
If you like it, download it. If you don't, umm, don't.
The download for the texture file is here: http://www.4shared.com/zip/uocBOE6k/block_texturespng.html
To install this, follow leddy231's instructions up to (and including) step 4.
Inside the Sphax texture pack archive you modified with Leddy231's patch, there will be a file in this path:
You need to replace this block_textures.png file with the one you downloaded from my download link above (you will need to open my file in an archive program to get to the actual texture file too - it will end in .png, NOT in .zip).
Once you've down the above, follow the rest of the steps in leddy231's instructions (steps 5 & 6), and enjoy!
All of the textures used were available in the original compilation uploaded by leddy231, which were in turn created by their respective owners - all I've done is mangle a few of the different textures together and added a colour overlay to the panel segments for these handy advanced generators. I take no privileges of ownership for these textures and bow to the superior artistic skills of the original creators.