The Radio Shack Minimus 7s were sold by the boatload, and are available inexpensively. There have been a number of modifications published in Audio Amateur/AudioXPress and online. One popular mod is the AudioKarma PZ2.1 circuit, discussed in this thread (almost a decade ago now):
It appears some of the photos and the crossover schematic are now missing, but I've included a graphic below with the crossover.
I've used this circuit to successfully modify a couple sets of these speakers for my kids and as desktop computer speakers.
Above: The frequency response of a stock Minimus 7 (aluminum cabinet version), using Omnimic in blended mode, 1/6th octave at about 20 inches. Low frequency rolloff at about 120 or 130 Hz, and the tweeter overall seems elevated with peaks around 2.5K and 8K.
I rebuilt a pair of the walnut cabinet version of the Minimus 7 with the PZ2.1 crossover.
Above is the frequency response of the modified unit, same setup as above.
Above: The crossover circuit. Click to enlarge