Design package?
Sure.. it's called MSPaint. Fine for simple 2-dimensional sketches, but if you wanna see how it's really done, check those on FLJ's site. Being that he's a CAD nut means that his have that... what's the word?.... Je ne sias quois?
My layouts are just drawn on a simple matrix template, 5" x 2.5" (50 holes by 25 tracks), but can be up to any size which your graphics card can handle. Since most circuits are smaller than 5 x 2.5 means I just copy/paste the size I need from the template. Anything bigger simply involves a bit more copy/pasting.
Like everything else, the simplicity comes at a price. Your 3.9" x 12" board is do'able, if a tad clumsy due to screen resolution. The screen res' layout is actually 46% larger than the real-world size of of the finished board, so your 12" board would be almost double in size on the screen. In order to get to the part of the the board that you're working on, would mean a lot of to'ing and fro'ing and scrolling. A bit fiddly, but no real biggie.
Each and every component is hand-drawn, all kept in a library. It's just a simple matter of copying the required component from the library, then pasting to the board. Can be a bit time consuming... especially when you're near the end of a particular layout just to discover the limitations of Veroboard for the umpteenth time, realising that the last component just won't go in, no way no how, forcing a re-shuffle and starting all over again.
Now do you feel a bit cheated for calling it a professional product?