-> Suggestion post here. <-
I suggest adding a new type of solar panels that does not have a casing and instead it just "folds". I do not know of any real world satellite that would have a casing for its solar panels. This is how I imagine the setting sliders:
• Rows - same as now
• Row size - same as now
• Deploy speed - same as now
• Deploy amount - setting this to anything below 100% will mean that the panels will not fold out completely, retaining a bit of a "zig-zag" look
• Cell width - the width of each cell
• Cell height - the height of each cell
The "size" slider would be completely replaced by the cell width/height sliders. Because there is no casing that needs to be scaled with the panels, the panels could very well be square, or rectangular.
• Corner shape - the smoothness of the cell corners
Again, most real satellites simply use rectangular panels.
With the current panels and their fixed cell shape, it is not possible to replicate pretty much any existing satellite's panel. And while it is pretty easy to just build custom solar panels using the fixed one and moving parts for a realistic replica, such custom panels would not be able to track the sun.
I suggest adding this as a standalone part instead of replacing the current panels, because the current encased panels still make sense when it comes to futuristic spacecraft that may be re-entering the atmosphere of other planets. In that case, retracting the panels into a casing is realistic.
When the career mode is released, the exposed panels may function as a lower-cost alternative for the encased ones. For example, if you're delivering a satellite into orbit inside a fairing, there is no need for a casing.
EDIT: to better visualise what I mean, here are some real world examples;
(the width and height values are just ratios, because I can't be bothered to find the actual dimensions of the satellite's panels)
Rows: 1, Row size: 2, Cell width: 1, Cell height: 2
Rows: 1, Row size: 5, Cell width: 2, Cell height: 1
Rows: 2, Row size: 2, Cell width: 1, Cell height: 2
Rows: 3, Row size: 1, Cell width: 1, Cell height: 2
I'd be happy with the stock solar panels with options to have it pre-extended or case-less.